ET 03-65 Appendix A

1.1 Background

As part of the overall spectrum management process, NTIA and the FCC have developed radio regulations to facilitate operation of various radio services in the same environment without unacceptable levels of radio interference. These regulations generally focus on sharing spectrum and the interfering potential of transmitters. Less attention has been given to the regulation of receiver parameters and the associated non-cochannel interference issues.

In recent years, there have been a number of cases of non-cochannel[1] interference that have been caused by the inadequate performance of receivers instead of by transmitter performance. One element in the prevention of non-cochannel interference and improvement in spectrum utilization efficiency is the design and use of receivers that are less susceptible to interference. Some of the reasons why these interference and efficiency problems are now becoming apparent may include:

1) continued dramatic increase in overall spectrum use;

2) mix of analog and digital technologies that have different spectral requirements, channel plans and interference suppression capabilities;

3) introduction of new services and systems without adopting standards needed for electromagnetic compatibility with incumbent services and systems;

4) design tradeoffs favoring inexpensive radio equipment rather than good equipment performance;

5) reduction or loss of previously available guard bands;

6) equipment manufacturers’ lack of knowledge of characteristics of equipment operating in the same or adjacent bands;

7) increased receiver front-end bandwidth associated with greater tuning range of certain receivers; and

8) different system channel plans in the same band e.g. specialized mobile radio (SMR) and public safety operations sharing the 800 MHz band.[2]

Receiver designs that do not take into adequate account the operational environment are often vulnerable to interference from non-cochannel signals because of inadequate dynamic range or selectivity within the Radio Frequency (RF) or Intermediate Frequency (IF) stages of the receiver. Some examples of interference due to inadequate receiver design that have been investigated by NTIA include the following:

1) Fixed-satellite service receiving earth stations that use low noise preamplifiers at the antenna and have little or no filtering prior to active components,[3]

2) Digital radio relay receivers that use low noise preamplifiers and have little or no filtering prior to active components,[4]

3) Unlicensed Part 15 receivers, such as garage door openers, that use very wide bandwidths,[5]

4) Analog television and other consumer receivers with generally very poor RF selectivity,[6] and

5) VHF maritime receivers with insufficient selectivity.[7]

In the U.S. regulatory environment, it sometimes is not clear whether interference problems resulting from design faults in the receiver are the responsibility of the receiver owner or the transmitter owner to resolve. Without standards, the quality of the receiver and its interference susceptibility is left to the buyer of a piece of radio equipment as an aspect of market-place choices. Nevertheless, user reaction to interference, in some cases public reaction, may place the onus on changing transmitter operations regardless of the actual cause of the interference.

The increased demands placed on the radio spectrum require effective spectrum management. Currently, efficient spectrum utilization is not achieved due to limitations on the assignment of adjacent or semi-adjacent channels in the same or nearby areas in some services. This results in many potential assignments being unavailable. One well-known example is the practice by the FCC not to assign adjacent analog television channels in the same area due to poor receiver selectivity. Had television receiver standards been implemented, this frequency assignment constraint would not have been necessary and there would have been adequate television channels to satisfy demand.[8]

In response to the Omnibus Budget Reconciliation Act of 1993 and the Balanced Budget Act of 1997, NTIA identified a total of 255 MHz of Federal spectrum for reallocation to the private sector to provide additional spectrum for emerging telecommunications technologies and to help balance the Federal budget through subsequent auction of the identified bands.[9] Because of the large spectrum requirements of the Federal Government and the mandate to avoid excessive costs or serious degradation to Federal operations, most of these bands were identified with some degree of encumbrance. These encumbrances include continued Federal operations within certain bands at specific sites and continued Federal operations in adjacent bands. Introduction of new services and systems in the 17 bands identified for reallocation will open up a significant number of potential adjacent band interference problems. In the Spectrum Reallocation Final Report, NTIA recognized the potential problems and recommended that effective receiver standards, either regulatory or established by industry, be developed for new technologies operating in the reallocated bands adjacent to high-power Federal systems.[10]

Domestically, there has been no clear consensus regarding the best means to assure development and use of suitably designed receivers. Previously, the FCC declined to mandate standards for commercial receivers, stating that the pressures of the marketplace provide the best means to accomplish this goal. In some commercial areas, such as Personal Communications Service (PCS), system designers have successfully applied receiver standards. In other areas, especially where the consumers have access to products that achieve significantly different levels of performance, the lack of known standards and compliance may make it difficult for them to make an informed choice.

1.2 Objectives

The objective of Phase 1 of this task was to undertake a broad review of receiver spectrum standards to characterize their status, both domestically and internationally. This Report presents the results of this phase.

Phase 2 will explore various alternatives and options to promote the use of receivers that are compatible with their operating environment, especially in commercial bands adjacent to Federal bands in which Federal high power equipment is operated. That phase will examine effectiveness trade-offs of various regulatory and voluntary approaches and develop appropriate recommendations.

1.3 Approach

Existing standards were compiled and reviewed in order to categorize the various types of standards and associated regulatory frameworks. In the sections that follow, particularly the tables, concise examples of different types of receiver standards are provided. For application of a standard, the complete referenced document should be consulted.[11]

Section 2
TECHNICAL BACKGROUND

This report focuses on potential non-cochannel interference of an unwanted transmitter on a victim receiver, and the standards that recommend receiver design parameters to prevent that interference.

There are two modes whereby an undesired transmitter can interfere with a non-cochannel receiver. The first mode, usually regulated via limits on emissions outside the transmitter’s authorized bandwidth, involves unwanted emissions from the transmitter falling in the receiver’s tuned channel. The second mode involves several possible undesired responses of the receiver to the fundamental emissions in the transmitter’s tuned channel. These modes are generally independent, the former being dependent on the transmitter’s modulation and output filtering, and the latter on the receiver’s selectivity, dynamic range, and intermodulation rejection capability. It is this second mode that is the subject of this report.

These non-cochannel interference mechanisms include:

· feed through of non-cochannel signals to the demodulator due to inadequate selectivity (filtering) at RF and IF stages;

· blocking due to an undesired very strong signal saturating the first amplifier stages and causing severe distortion

· receiver desensitization resulting from erroneous automatic gain control responses to non-cochannel signals;

· gain compression due to inadequate RF selectivity and dynamic range;

· spurious responses (to non-cochannel signals that mix with locally
generated signals and fall within the receiver passband); and

· intermodulation of the desired and non-cochannel signals or two or more non-cochannel signals in non-linear stages of a receiver (e.g., in connection with gain compression).

The definitions of terms used to specify receiver standards vary among standardization bodies, especially for technical definitions that describe the means for measuring compliance. Thus, the source documents and associated publications, as well as the IEEE Standard Dictionary of Electrical and Electronics Terms, ITU Recommendation SM.332-4, Selectivity of Receivers, and Federal Standard 1037C, Telecommunications: Glossary of Telecommunications Terms, should be consulted for proper interpretation and application of the standards. Following are generalized definitions for receiver parameters and other technical terms used in this report:

· Adjacent Channel – A channel with bandwidth equal to, and abutting the desired signal channel.

· Adjacent Channel Rejection (attenuation) – The ability of a receiver to reject signals in the adjacent channel.

· Adjacent Channel Selectivity – The ability of a receiver to discriminate between a desired signal and an undesired signal in an adjacent channel.

· [BJ1] Blocking – Saturation of the front end amplifier stage of a receiver by an undesired signal on a frequency different from that of the desired signal, thereby causing severe distortion and other non-linear effects that prevent proper operation of the receiver. This is also called the receiver saturation or blanking.

· Cross Modulation – The appearance of modulation from an unwanted signal on the desired signal.

· Image Frequency (of a heterodyne receiver) – The frequency removed from the local oscillator frequency, in the direction opposite to the direction of the desired signal frequency, by an amount equal to the intermediate frequency (i.e., difference between the desired channel frequency and the local oscillator frequency).

· Image Frequency Rejection – The ability of a receiver to reject signals at the image frequency.

· Intermodulation Rejection – The ability of a receiver to reject intermodulation products produced by the mixing of two or more signals at the input to the receiver.

· Necessary Bandwidth – For a given class of emission, the width of the frequency band which is just sufficient to ensure the transmission of information at the rate and with the quality required under specified conditions.

· Non-Cochannel Signal – Any signal or portion of a signal falling outside the authorized bandwidth of the desired signal.

· Occupied Bandwidth – The width of a frequency band such that, below the lower and above the upper frequency limits, the mean powers emitted are each equal to a specified percentage β/2 of the total mean power of a given emission. Unless otherwise specified, the value of β/2 should be taken as 0.5%. β equals the percentage of power outside the occupied bandwidth frequency limits.

· Out-of-Band Emission – Emission on a frequency or frequencies immediately outside the necessary bandwidth that result from the modulation process, but excluding spurious emissions.

· Selectivity – Rejection (attenuation) of an undesired signal at frequencies close to the desired signal frequency. It is often specified as the amount of frequency difference between desired and undesired signals needed to produce a specified attenuation of the undesired signal.

· Sensitivity Depression or Desensitization – The level of a non-cochannel signal that increases a receiver signal power threshold or decreases receiver gain by a defined amount.

· Spurious Emission – Emission on a frequency or frequencies which are outside the necessary bandwidth and the level of which may be reduced without affecting the corresponding transmission of information. Spurious emissions include harmonic emissions, parasitic emissions, intermodulation products and frequency conversion products, but exclude out-of-band emissions.

· Spurious Response – Undesired receiver response resulting from mixing of the local oscillator and undesired signals. This includes the response to undesired signals at the image frequency.

· Unwanted Emissions – Both spurious emissions and out-of-band emissions.

Section 3
FEDERAL AGENCY STANDARDS

3.1 National Telecommunications And Information Administration (NTIA)

NTIA is responsible for managing Federal Government use of the radio spectrum. Its regulations, pertaining to Federal Government use of the frequency spectrum, are contained in the Manual of Regulations and Procedures for Federal Radio Frequency Management.[12]

[BJ2] The NTIA Manual provides receiver standards for most fixed systems below 15 GHz, most mobile systems below 420 MHz, and most radar systems as shown in Table 1. Generally, these standards include requirements for selectivity, spurious response rejection, and intermodulation rejection. These standards cover a large percentage of the authorized assignments in the Government Master Frequency File,[13] including the most congested Very High Frequency (VHF) and Ultra High Frequency (UHF) bands.

Table 1. Summary of NTIA Receiver Standards
NTIA Manual Section	Frequency Band	Service	Parameter	Requirement
3.9.7	162-174 MHz	VHF Inter-national Boundary and Water Commission	Selectivity	90 dB
			Intermodulation Rejection	80 dB
			Spurious & Image Rejection	100 dB
5.3.1	HF 3 – 30 MHz	Fixed & Mobile	Selectivity	The pass band shall be no greater than the authorized bandwidth of emission and the slope of the selectivity outside the pass band shall be 100 dB/kHz
5.3.3	406.1 - 420 MHz, 932-935/941-944 MHz, 1.71 - 15.35 GHz	Fixed	Spurious Rejection	The receiver unwanted signals shall be attenuated at least 60 dB relative to the receiver sensitivity at the center of the pass band
5.3.3	406.1 - 420 MHz, 932-935/941-944 MHz, 1.71 - 15.35 GHz	Fixed	Selectivity	The 3 dB receiver bandwidth should be commensurate with the authorized emission bandwidth plus twice the frequency tolerance of the transmitter. The 60 dB receiver bandwidth shall not exceed five times the 3 dB receiver bandwidth

Table 1. Summary of NTIA Receiver Standards (continued)
NTIA Manual Section	Frequency Band	Service	Parameter	Requirement
5.3.5.1	29.7-50 MHz, 162-174 MHz, 406.1-420 MHz	Fixed & Mobile (Wide Band)	Spurious Rejection	All exc. portable: 85 dB Portable: 50-60 dB (depending on band)
			Adjacent Channel Rejection (Analog)	All exc. portable: 80 dB Portable: 50-70 dB
			Adjacent Channel rejection (Digital)	All exc. portable: 50-55 dB Portable: 50 dB
			Intermodulation Rejection	All exc. portable: 60-70 dB Portable: 50 dB
5.3.5.2	138-150.8 MHz, 162-174 MHz, 406.1-420 MHz	Fixed & Mobile (Narrow Band)	Spurious Rejection	All exc. portable: 70 dB Portable: 60 dB
			Adjacent Channel Rejection	All exc. portable: 60-70 dB Portable: 50-60 dB
			Intermodulation Rejection	All exc. portable: 70 dB Portable: 50 dB
5.5.2	2.9-40 GHz	Radars (Criteria B)	Selectivity	The overall receiver selectivity characteristics shall be commensurate with or narrower than the transmitter bandwidth
			Spurious Rejection, excluding image	50 dB, except where broadband front ends are required
			Stability	Frequency stability of receivers shall be commensurate with, or better than that of the associated transmitter
5.5.3	All Radar Bands	Radars (Criteria C)	Selectivity	The overall receiver selectivity characteristics shall be commensurate with or narrower than the transmitter bandwidth. Receivers shall be capable of switching bandwidth limits to appropriate values whenever the transmitter bandwidth is switched
			Spurious Rejection, excluding image	60 dB
			Image rejection	50 dB
			Stability	Frequency stability of receivers shall be commensurate with, or better than that of the associated transmitter
5.5.4	2.7-2.9 GHz	Radars (Criteria D)	Selectivity	The overall receiver selectivity characteristics shall be commensurate with or narrower than the transmitter bandwidth. Receivers shall be capable of switching bandwidth limits to appropriate values whenever the transmitter bandwidth is switched
			Spurious Rejection, excluding image	60 dB
			Image Rejection	50 dB
			Stability	Frequency stability of receivers shall be commensurate with, or better than that of the associated transmitter
			Receiver Interference Suppression Circuitry	Radar systems should ha [BJ3] [BJ4] ve provisions incorporated into the system to suppress pulsed interference. The following information is intended for use as an aid in the design and development of receiver signal processing circuitry or software to suppress asynchronous pulsed interference. A description of the parametric range of the expected environmental signal characteristics at the receiver IF output is: Peak I/N ratio:<50 dB Pulse width: 0.5 to 4.0 μs PRF: 100 to 2000 pps
5.5.5	449 MHz	Radar (Criteria E, Wind Profiler Radars)	Selectivity	The 3 dB receiver bandwidth should be commensurate with the authorized emission bandwidth plus twice the transmitter frequency tolerance of 10 parts per million (ppm). The 60 dB receiver bandwidth shall be commensurate with the 60 dB emission bandwidth. Receivers shall be capable of switching bandwidth limits to appropriate values whenever the transmitter bandwidth is switched
			Spurious rejection, excluding image	60 dB
			Image Rejection	50 dB
			EMC Provision	Radars shall have the capability to tolerate incoherent pulsed interference of duty cycles less than 1.5 percent such that peak interfering signal levels 30 dB greater than the receiver noise level at the IF output will not degrade performance
8.2.29	156-162 MHz	Maritime Mobile	Adjacent Channel Selectivity	70 dB fixed 40 dB portable
8.2.29	156-162 MHz	Maritime Mobile	Spurious Rejection	85 dB fixed 50 dB portable
Note: This table is a summary only. Reference should be made to the NTIA Manual for the full text of the standard.

3.2 Federal Communications Commission (FCC)

The FCC is responsible for regulation of spectrum use by the private sector and non-Federal agencies. Its regulations are published in Title 47 of the Code of Federal Regulations. Generally, the FCC has not mandated receiver standards in the past. Instead, it has relied on the market place to encourage manufacturers to design receivers to whatever specifications are required for market place acceptance. Two exceptions have been in the area of cable-ready television receivers and unlicensed devices authorized under FCC Part 15 rules.

The FCC established the Spectrum Policy Task Force to study methods of improving spectrum management. This Task Force recommended that the FCC consider adopting receiver spectrum standards. The FCC has recently released a Notice of Inquiry (NOI) on this subject.[14]

Part 15.17 of the FCC rules, Radio Frequency Devices, has receiver standards pertaining to non-licensed devices. It advises parties responsible for equipment compliance to consider the proximity and the high power of non-government licensed radio stations, such as broadcast, amateur, land mobile, and non-geostationary mobile satellite feeder link earth stations, and U.S. Government radio stations, which could include high-powered radar systems, when choosing operating frequencies during the design of their equipment to reduce the susceptibility to receive harmful interference. Information on non-government use of the spectrum can be obtained by consulting the Table of Frequency Allocations in the FCC rules. Information on U.S. Government operations can be obtained by contacting the Director for Spectrum Plans and Policy within the National Telecommunications and Information Administration.[15]

This is an example of an approach to prevent interference, which is based on the expectation that manufacturers or operators characterize the electromagnetic environment in which the receiver will operate and develop appropriate voluntary standards or equipment specifications for receiver compatibility.

Part 15.118 of the FCC rules on cable ready consumer electronics equipment gives standards for receivers labeled as cable ready. It provides very detailed requirements and measurement methods for adjacent channel interference, image channel interference, direct pickup interference, and tuner overload.[16]

In another area, while not setting a standard, the FCC’s October 1984 Memorandum Opinion and Order for changes to rules related to educational FM stations recognized the work of the Electronic Industry Association/Consumer Electronics Group (EIA/CEG). The FCC acknowledges that it considers this work essential because insufficient information is now available to allow the drafting of standards for this service. The FCC recommends that the EIA Committee fill that void by providing guidance for improved receivers. The FCC emphasizes this point by stating that “if the industry, for whatever reasons, is unable or unwilling to set its own receiver standards, it may be necessary for the FCC to step in.” The Order further states that “the FCC may, upon review, determine that voluntary compliance by receiver manufacturers with EIA guidelines is appropriate, and we may be able to begin relaxing the assignment criteria as market penetration of the improved receivers expands.” [17] Ultimately, it could also decide to provide interference protection only to those receivers meeting minimum interference standards.

3.3 Department Of Defense (DOD)

Receiver standards for the military are published by the U.S. Department of Defense. They pertain to all procurements by the various military departments. The primary DOD receiver spectrum standards are contained in two documents: MIL-STD 461E, Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment, and MIL-STD 469B, Radar Engineering Interface Requirement, Electromagnetic Compatibility.

MIL-STD 461E is the primary military standard relating to receiver spectrum standards.[18] The provisions of this standard primarily concern high-level radiation that may cause damage to the receiver, but Appendix A gives examples of various limits for different conditions for susceptibility to non-cochannel emissions. It includes a requirement to provide normal operation with an unwanted signal of 0 dBm outside of the tuning range of the receiver and also for an unwanted signal of 80 dB above the desired signal within the tuning range. There is also a cross modulation requirement for continued operation with a Carrier-to-Interference power ratio (C/I) of -66 dB. It also includes limits for bulk cable injection, power line interference, and general environmental levels. It provides detailed test procedures for measuring receiver parameters.

The second standard, MIL-STD 469B, contains receiver bandwidth, spurious responses, and image rejection for various classes of radars.[19] The standard and requirements are shown in Table 2. Many of these standards are derived from the NTIA standards.

Table 2. MIL-STD 469B Requirements for radar receivers

Radar category[20]	Group[21]	Requirements
1	B, C, D	The overall receiver selectivity characteristics shall be more narrow than the transmitter bandwidth described in tables IV, V, and VI[22] for the respective group. The minimum frequency range over which the receiver acceptance bandwidth and susceptibility requirements apply shall be the F _MIN to F _MAX range in table VI.
1	B	Receiver rejection of spurious responses, other than image responses, shall be 50 dB or better except where broadband front ends are required operationally.
1	C, D	Receivers shall be capable of switching bandwidth limits to appropriate values whenever the transmitter bandwidth is switched (pulse shape changed). Receiver image rejection shall be at least 50 dB; rejection of all other spurious responses shall be at least 60 dB.
2	B,C	The required acceptance bandwidth is the receiver acceptance bandwidth which includes the fundamental frequency response and extends from the lowest to the highest frequencies on the selectivity curve outside of which all other responses are at least 80 dB below the fundamental frequency response. Required acceptance bandwidths are listed: Type modulation Required acceptance bandwidth (MHz) Non-FM pulse 20/t FM pulse 20d/t CW 3 × 10 ^-4 F_o FM/CW 3 × 10 ^-4 F_o + B_d The radar receiver shall not exhibit any undesired response when subjected to signals outside the acceptance bandwidth. RF preselection shall be employed except where broadband front ends are required operationally. The requirement for broadband front ends will be determined by the contracting activity and incorporated into the equipment or subsystem request-for-proposal, specification, contract, or order. The minimum frequency range over which the receiver susceptibility characteristics apply shall be the F _MIN to F _MAX range in table VI for Category 2 radars.

Radar category[20]

Group[21]

Requirements

B, C, D

The overall receiver selectivity characteristics shall be more narrow than the transmitter bandwidth described in tables IV, V, and VI[22] for the respective group. The minimum frequency range over which the receiver acceptance bandwidth and susceptibility requirements apply shall be the F _MIN to F _MAX range in table VI.

Receiver rejection of spurious responses, other than image responses, shall be 50 dB or better except where broadband front ends are required operationally.

C, D

Receivers shall be capable of switching bandwidth limits to appropriate values whenever the transmitter bandwidth is switched (pulse shape changed). Receiver image rejection shall be at least 50 dB; rejection of all other spurious responses shall be at least 60 dB.

B,C

The required acceptance bandwidth is the receiver acceptance bandwidth which includes the fundamental frequency response and extends from the lowest to the highest frequencies on the selectivity curve outside of which all other responses are at least 80 dB below the fundamental frequency response. Required acceptance bandwidths are listed:

Type modulation Required acceptance bandwidth (MHz)

Non-FM pulse 20/t

FM pulse 20d/t

CW 3 × 10 ^-4 F_o

FM/CW 3 × 10 ^-4 F_o + B_d

The radar receiver shall not exhibit any undesired response when subjected to signals outside the acceptance bandwidth. RF preselection shall be employed except where broadband front ends are required operationally. The requirement for broadband front ends will be determined by the contracting activity and incorporated into the equipment or subsystem request-for-proposal, specification, contract, or order. The minimum frequency range over which the receiver susceptibility characteristics apply shall be the F _MIN to F _MAX range in table VI for Category 2 radars.

3.4 Federal Aviation Administration (FAA)

The Federal Aviation Administration is responsible for regulations pertaining to flight operations. For communications and navigation equipment, the FAA publishes Technical Standard Orders (TSOs) which refer to Radio Technical Commission for Aeronautics (RTCA) standards for their technical requirements.[23] Some of the TSOs are voluntary, at least for certain applications, and some are mandatory. For instance, in order to be identified with the applicable TSO marking, TSO-C32d prescribes that HF radio receiving equipment must meet the standards set forth in RTCA Document No. DO-163, Minimum Performance Standards - Airborne High Frequency Radio Communications Transmitting and Receiving Equipment Operating Within the Radio Frequency Range 1.5-30 Megahertz. [24] For their own receivers, the FAA uses procurement specifications for VHF/UHF AM Air/Ground Radio Communication Receivers. The specifications are given in Table 3.[25]

Table 3. FAA VHF/UHF AM Air/Ground Radio Communication Receiver Specifications

Parameter	Requirement
Selectivity, +/- 9 kHz	6 dB
Selectivity, +/- 25 kHz	60 dB
Spurious response rejection	70 dB
Desensitization	80 dB
Intermodulation rejection	75 dB
Cross Modulation rejection (+/- 0.5 MHz)	70 dB
Cross Modulation rejection (+/- 1.0 MHz)	75 dB
Cross Modulation rejection (+/- 1.5 MHz)	80 dB

3.5 Department Of Agriculture

The Department of Agriculture has requirements given in their Minimum Standard Specifications for Analog Only FM Land Mobile Radio Communications Equipment.[26] Test methods and definitions are based primarily on TIA/EIA–603–A, Land Mobile FM or PM Communications Equipment Measurements and Performance Standards but include additional limits. These specifications are given in Table 4, Table 5, and Table 6. [27] The Department of Agriculture specifications are unique because they have separate specifications for Economy, Standard, and High Performance equipment. This concept may also be applicable for the private sector because it could enable consumers to make purchase decisions based on required performance and cost.

Table 4. Department of Agriculture VHF Low-Band Receiver Specifications

Parameter	Type	Economy	Standard	High Perfor-mance
Adjacent Channel Selectivity	Portable	70 dB	N/A	75 dB
	Mobile	70 dB	80 dB	85 dB
	Base	N/A	85 dB	85 dB
Spurious Rejection	Portable	65 dB	N/A	70 dB
	Mobile	80 dB	80 dB	90 dB
	Base	N/A	85 dB	100 dB
Intermod-ulation Rejection	Portable	60 dB	N/A	65 dB
	Mobile	70 dB	75 dB	75 dB
	Base	N/A	75 dB	75 dB
Note: N/A = Not Applicable

Table 5. Department of Agriculture VHF High-Band Receiver Specifications

Parameter	Type	Wideband			Narrowband
Parameter	Type	Economy	Stan-dard	High Perfor-mance	Economy	Stan-dard	High Perfor-mance
Adjacent Channel Selectivity	Portable	70 dB	75 dB	75 dB	60 dB	63 dB	65 dB
	Mobile	70 dB	80 dB	85 dB	70 dB	70 dB	73 dB
	Base	85 dB	85 dB	85 dB	78 dB	78 dB	80 dB
	Aviation	80 dB	N/A	N/A	70 dB	N/A	N/A
Spurious Rejection	Portable	70 dB	70 dB	75 dB	70 dB	70 dB	75 dB
	Mobile	80 dB	80 dB	90 dB	80 dB	80 dB	80 dB
	Base	80 dB	85 dB	100 dB	80 dB	85 dB	100 dB
	Aviation	85 dB	N/A	N/A	80 dB	N/A	N/A
Intermod-ulation Rejection	Portable	65 dB	65 dB	75 dB	65 dB	65 dB	65 dB
	Mobile	70 dB	75 dB	75 dB	70 dB	70 dB	70 dB
	Base	75 dB	75 dB	75 dB	70 dB	70 dB	75 dB
	Aviation	70 dB	N/A	N/A	70 dB	N/A	N/A

Table 6. Department of Agriculture UHF Receiver Specifications

Parameter	Type	Wideband			Narrowband
Parameter	Type	Economy	Stan-dard	High Perfor-mance	Economy	Stan-dard	High Perfor-mance
Adjacent Channel Selectivity	Portable	70 dB	N/A	75 dB	60 dB	N/A	65 dB
	Mobile	70 dB	80 dB	85 dB	70 dB	70 dB	73 dB
	Base	75 dB	85 dB	85 dB	75 dB	78 dB	80 dB
	Aviation	80 dB	N/A	N/A	70 dB	N/A	N/A
Spurious Rejection	Portable	70 dB	N/A	75 dB	70 dB	N/A	75 dB
	Mobile	80 dB	80 dB	90 dB	80 dB	80 dB	80 dB
	Base	75 dB	85 dB	100 dB	75 dB	85 dB	100 dB
	Aviation	85 dB	N/A	N/A	80 dB	N/A	N/A
Intermod-ulation Rejection	Portable	65 dB	N/A	75 dB	65 dB	N/A	65 dB
	Mobile	70 dB	75 dB	75 dB	70 dB	70 dB	70 dB
	Base	70 dB	75 dB	75 dB	70 dB	70 dB	75 dB
	Aviation	70 dB	N/A	N/A	70 dB	N/A	N/A

Section 4
U.S. INDUSTRY ASSOCIATION STANDARDS

4.1 Telecommunications Industry Association (TIA)

The Telecommunications Industry Association, in conjunction with the Electronic Industries Association (EIA), publishes recommended standards designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting purchasers in selecting and obtaining with minimum delay, the proper products for their particular needs. Adherence to their standards, which is very widespread, is entirely voluntary. There is close coordination between TIA and the various international standards organizations. Some examples from their standards include the following:

TIA/EIA TSB 10-F, Interference Criteria for Microwave Systems provides a methodology and criteria for properly coordinating microwave systems in merged bands. This bulletin provides guidance and examples for interference protection and coordination in the microwave bands but it does not give specific receiver standards.[28]

TIA /EIA -690, Recommended Minimum Standards for 800 MHz Cellular Subscriber Units provides minimum standards for cellular subscriber units. It includes the receiver requirements shown Table 7.[29]

Table 7. TIA-690 Requirements for 800 MHz Cellular Subscriber Units

Parameter	Requirement
Adjacent channel rejection	16 dB
Semi-Adjacent channel rejection	60 dB
Intermodulation rejection	55 dB
Spurious Response Rejection	60 dB

TIA/ EIA–382–A, Minimum Standards - Citizens Band Radio Service Amplitude Modulated (AM) Transceivers Operating in the 27 MHz Band provides definitions, methods of measurement, and minimum standards for Citizens Band receivers. This standard includes requirements for receivers as shown in Table 8.[30]

Table 8. TIA-382-A Requirements for CB AM Transceivers in the 27 MHz Band

Parameter	Requirement
Adjacent channel rejection	35 dB
Alternate channel rejection	35 dB
Receiver desensitization immunity	35 dB
Spurious response rejection	30 dB
Cross Modulation rejection	25 dB
Intermodulation rejection	40 dB
Impulse Noise Limiter and Blanking	10 dB

TIA–603–A, Land Mobile FM or PM Communications Equipment Measurements and Performance Standards provides methods of measurements for receivers and gives detailed procedures on making measurements of adjacent channel rejection, offset channel selectivity, spurious response rejection, intermodulation rejection, and blocking rejection. This standard is widely referenced in the industry for methods of making measurements. This standard addresses Class B (standard performance) and Class A (high interference rejection) equipment as shown in Table 9. This is similar to the Department of Agriculture requirements for Economy, Standard, and High Performance equipment.[31]

Table 9. TIA-603-A Requirements for Land Mobile FM and PM Equipment

Type Service	Response	Applicable Channelization	Fixed	Mobile	Portable
Class A	Adj Channel rejection	>20 kHz	75 dB	75 dB	70 dB
Class B	Adj Channel rejection	>20 kHz	70 dB	70 dB	60 dB
Class A	Adj Channel rejection	15 kHz	65 dB	65 dB	65 dB
Class B	Adj Channel rejection	15 kHz	60 dB	60 dB	60 dB
Class A	Adj Channel rejection	12.5 kHz	45 dB	45 dB	45 dB
Class B	Adj Channel rejection	12.5 kHz	40 dB	40 dB	40 dB
Class A	Spurious rejection	N/A	75 dB	75 dB	75 dB
Class B	Spurious rejection	N/A	70 dB	70 dB	60 dB
Class A	Intermodulation rejection	N/A	75 dB	75 dB	70 dB
Class B	Intermodulation rejection	N/A	70 dB	70 dB	50 dB
All	Offset channel selectivity	N/A	20 dB	20 dB	20 dB
Class A	Blocking Rejection	N/A	90 dB	90 dB	80 dB
Class B	Blocking Rejection	N/A	80 dB	80 dB	70 dB

4.2 Consumer Electronics Association (CEA)

The CEA, in conjunction with the EIA, publishes standards related to consumer electronics. It has two standards applicable to receiver susceptibility: EIA/IS-31, Recommended Design Guideline, Rejection of Educational Interference to Channel 6 Television Reception, and EIA/IS-16-A, Immunity of Television Receivers and Video Cassette Recorders (VCRs) to Direct Radiation From Radio Transmissions, 0.5 to 30 MHz.

The first standard, EIA/IS-31, establishes design guidelines for color television receivers and Video Cassette Recorders (VCR’s) for providing rejection of educational and non-commercial Frequency Modulated (FM) broadcast interference.[32] It was prepared to permit more educational FM licenses to be awarded. It provides for three levels of desired television channel 6 reception with specific FM signals in the educational FM band of 88.1 to 91.9 MHz. It provides a chart plot of the undesired to desired signal power ratio that causes a noticeable level of interference vs. frequency offset of the FM channel from television channel 6.[33]

The second standard, EIA/IS-16-A, establishes performance guidelines for the immunity of television receivers and VCR’s to radio transmissions below 30 MHz and provides recommended measurement procedures. It was established in response to the large number of complaints by consumers of interference from amateur radio, citizens band and AM radiobroadcast stations to television receivers in the early days of television. It states that an AM broadcast, amateur radio, or Citizens Band (CB) signal of 1 volt per meter (V/m), or any other emission within the 0.5 to 30 MHz band of 0.3 V/m shall not cause noticeable interference to either the video or the audio of a television receiver.[34]

4.3 Radio Technical Commission For Aeronautics (RTCA)

RTCA is an association of aeronautical organizations of the United States from both government and industry. It is dedicated to the advancement of aeronautics, seeking sound technical solutions to problems involving the application of electronics and telecommunications to aeronautical operations. The association’s objective is to resolve conflicts by mutual agreement of its member organizations. RTCA is not an official agency of the United States government and its recommendations may not be regarded as statements of official government policy unless so enunciated by the government organization or agency having statutory jurisdiction over any matters to which the recommendations relate. Many RTCA recommendations are indeed included in TSO’s of the FAA.

RTCA has numerous standards for avionics. Due to the critical nature and safety of flight issues related to aviation communication and navigation, RTCA standards are considerably more detailed than most other standards. Below is a representative sample of RTCA standards relating to receiver susceptibility to interference.

4.3.1 RTCA/DO-143, Minimum Operating Performance Standards for Airborne Radio Marker Receiving Equipment Operating on 75 MHz

RTCA/DO-143 has requirements for sensitivity depression, cross modulation, and spurious response for receivers operated in the landing approach mode. There are also additional requirements for receivers operated in the enroute mode. As an example, requirements for sensitivity depression caused by out of band broadcast signals include requirements that the level of a standard test signal required to produce receiver threshold shall not increase more than 4 dB when there is added a channel 4 or 5 television signal having a level of 3.5 volts, and also that the level of a standard test signal required to produce receiver threshold shall not increase more than 4 dB when a 0.5 volt FM RF signal is present between 72.02 to 74.58 MHz and 75.42 to 75.98 MHz.[35]

4.3.2 RTCA/DO-177, Minimum Operating Performance Standards for Airborne Receiving Equipment for Microwave Landing Systems

RTCA/DO-177 has non-cochannel interference rejection standards that require that normal operational specifications shall be met in the presence of clear wave signals between 5000 MHz and 5250 MHz, at -55 dBW, excluding the band 5030 to 5091.7 MHz. Normal operational specifications shall also be met with interfering signals between 5250 MHz and 12.4 GHz at -20 dBm. Normal operational specifications shall also be met in the presence of C-Band weather radars in the 5350 to 5470 MHz band.[36]

4.3.3 RTCA/DO-179, Minimum Operating Performance Standards for Airborne Radio Direction Finding Equipment

RTCA/DO-179 applies to AM equipment operating in the Medium Frequency (MF) bands. It gives receiver selectivity requirements to be met in the presence of RF signal field strengths producing a defined receiver output at specified frequencies off resonance. Two criteria are given, one for simply being able to receive the non-directional beacon (NDB) audio, and the second for a maximum bearing error permitted in the automatic direction finding (ADF) mode as shown in Table 10. This standard also contains spurious response rejection requirements for signals from 50 kHz to 150 MHz as shown in Table 11 and cross modulation requirements as shown in Table 12.^{^[37]}

Table 10. RTCA DO-179 Selectivity requirements of for ADF Receivers

Carrier offset frequency	NDB mode	ADF mode
0 kHz	0 dB	NA
1 kHz	0 dB	-10 dB
1.5 kHz	6 dB	-4 dB
2 kHz	12 dB	2 dB
3 khz	27 dB	17 dB
4 kHz	42 dB	32 dB
5 kHz	57 dB	47 dB
6 kHz	72 dB	62 dB
7 kHz	>80 dB	>70 dB

Table 11. RTCA DO-179 Spurious Response requirements for ADF Receivers

Carrier tuning range	Response attenuation
190 – 850 kHz	80 dB
> 850 kHz	60 dB

Table 12. RTCA DO-179 Cross Modulation Requirements for ADF Receivers

Frequency Range	Undesired modulated signal	Desired unmodulated signal (µvolts per meter)
50kHz - 550 kHz	100 µvolts/meter - 0.2 volt/meter	100 µvolts/meter - 0.2 volt/meter
550 kHz – 150 MHz	100 µvolts/meter - 1 volt/meter	100 µvolts/meter - 0.2 volt/meter
Note: µvolts = microvolts

4.3.4 RTCA/DO-186A, Minimum Operating Performance Standards for Airborne Radio Communications Equipment operating within the Radio Frequency Range 117.975 to 137 MHz

RTCA/DO186A is an example of a standard that goes into great detail. It defines six classes of receivers, depending on the channelization and the capability of offset carrier operation. Some of the specifications include the following requirements:[38]

Skirt Bandwidth (Selectivity)

Class A receivers utilize a 50 kHz channel separation environment having offset carrier operation. Class B receivers utilize the same separation environment but not having offset carrier operation. For these receivers the requirement is that at a frequency displaced by 43 kHz on either side of the assigned channel frequency, the level of an input signal required to produce reference Automatic Gain Control (AGC) voltage shall be at least 60 dB greater than the level required to produce reference AGC voltage at the assigned channel frequency.

Class C receivers utilize a 25 kHz channel separation environment having offset carrier operation. For these receivers the requirement is that at frequencies displaced by 17 and 25 kHz on either side of the assigned channel frequency, the input signal level required to produce reference AGC voltage shall be at least 40 dB and 60 dB respectively, greater than the level required to produce reference AGC voltage at the assigned channel frequency.

Class D receivers utilize a 25 kHz channel separation environment not having offset carrier operation. For these receivers the requirement is that at a frequency displaced by 22 kHz on either side of the assigned channel frequency, the input signal level required to produce reference AGC voltage shall be at least 60 dB greater than the level required to produce reference AGC voltage at the assigned channel frequency.

Class E receivers utilize a 8.33 kHz channel separation environment not having offset carrier operation.

ADF	Automatic Direction Finding
AGC	Automatic Gain Control
AM	Amplitude Modulated
CB	Citizens Band
CEA	Consumer Electronics Association
CW	Continuous Wave
dB	decibels
dBm	decibels above one milliwatt
dBW	decibels above one watt
DME	Distance Measuring Equipment
DOD	Department of Defense
EIA	Electronic Industries Association
EMC	Electromagnetic Capability
ETSI	Electronic Telecommunications Standards Institute
FAA	Federal Aviation Administration
FAR	Federal Aviation Regulation
FCC	Federal Communications Commission
FM	Frequency Modulation
HF	High Frequency (3 to 30 MHz)
ICAO	International Civil Aviation Organization
IEC	International Electrotechnical Commission
IEEE	Institute of Electrical and Electronics Engineers
ILS	Instrument Landing System
IM	Intermodulation
IMO	International Maritime Organization
ITU	International Telecommunications Union
kHz	Kilohertz
kW	Kilowatt
MF	Medium Frequency (.3 to 3 MHz)
MHz	Megahertz
MIL-STD	Military Standard
NDB	Non-Directional Beacon
NTIA	National Telecommunications and Information Administration
PCS	Personal Communications Service
PM	Phase Modulated
RTCA	Radio Technical Commission for Aeronautics
RTCM	Radio Technical Commission for Maritime Services
SMR	Specialized Mobile Radio
TIA	Telecommunications Industry Association
TSO	Technical Standard Order
UHF	Ultra High Frequency (300 to 3000 MHz)
VHF	Very High Frequency (30 to 300 MHz)
VOR	VHF Omni-directional Range
µvolt	Microvolt
V/m	Volts per meter