RSS-181 — Coast and Ship Station Single Sideband Radiotelephone Transmitters and Receivers Operating in the 1,605–28,000 kHz Band

9. Minimum Standards (Receivers)

9.1 Sensitivity

9.1.1 Definition - The sensitivity of a receiver is the minimum value of the input signal which will produce at least 50% of the receiver's rated audio power output with a ratio of signal + noise + distortion to noise + distortion (SINAD) of 12 dB or better.

9.1.2 Methods of Measurement

9.1.2.1 A3J - Standard Input Signal Source (A) shall be applied to the receiver input terminals at a frequency which results in an audio frequency signal across the Standard Output Termination. The level of the signal source shall be adjusted until the SINAD ratio is 12 dB. At this level of signal input, it shall be possible to obtain 50% of the rated audio power output. If it is not possible to obtain 50% of the rated audio power output, the rf signal input shall be increased until 50% of rated audio power output is obtained and this value of rf signal input shall be used in specifying sensitivity.

9.1.2.2 A3/A3H - The test specified in (9.1.2.1) above shall be repeated with the receiver operating in the A3/A3H mode and Standard Input signal source (B).

9.1.3 Minimum Standards - The sensitivity shall be:

In the A3J mode - not more than 1.5 microvolts across 50 ohms or an equivalent input power.

In the A3/A3H mode - not more than 3 microvolts across 50 ohms or an equivalent input power.

9.2 Receiver Frequency Stability

9.2.1 Definition - The frequency stability is the ability of the receiver to maintain the Test Frequency as defined below.

9.2.2 Method of Measurement -The receiver shall be operated in the A3J mode. The frequency of the signal source and the frequency of the audio output shall be measured with frequency meters whose accuracies are ±3 Hz or better. The equipment shall have a maximum warm-up period of 30 minutes under standby conditions, i.e. filaments and oven power "on". The receiver shall then be placed in operation. The Standard Input Signal Source (a) shall be applied to the receiver input terminals at a radio frequency which results in a recovered audio frequency of 1000 Hz at the receiver output terminals. During the measurement period, the frequency drift of the 1000 Hz output signal shall be corrected for any drift occurring in the signal source. The audio output frequency shall be measured at one minute intervals over a 1 - hour period. The Test Frequency shall be computed as the mean frequency of all frequency measurements.

9.2.3 Minimum Standard - The recovered audio frequencies shall not differ from the Test Frequency by more than:

Category L ± 20 Hz
Categories C,V ± 60 Hz
Category Y ± l00 Hz

9.3 Two-Signal Selectivity and Desensitization Characteristics

9.3.1 Definition - The two-signal selectivity and desensitization characteristic of a receiver is a measure of its ability to separate a desired signal from an undesired signal on a nearby frequency.

9.3.2 Methods of Measurement

9.3.2.1 A3J Mode - Two unmedullated signal generators shall be equally coupled to the input of the receiver in such a fashion that they do not re-act upon one another and in combination present a correct impedance match to the input circuit. With the output of Generator #2 at zero, Generator #1 shall be applied at a frequency results in peak response at the terminated output terminals of the receiver and the signal level adjusted until the SINAD ratio is 12 dB. The frequency of Generator #2 shall be adjusted above and below the frequency of Generator #1, at a sufficient number of points to plot a curve. At each frequency setting the level of Generator #2 shall be adjusted until the SINAD ratio is reduced to 6 dB.

9.3.2.2 A3/A3H Mode - The measurements made for A3J above shall be repeated in the A3/A3H mode except that Generator #1 shall be modulated 30% by a 1000 Hz sinusoidal wave and Generator #2 modulated 30% by a 400 Hz sinusoidal wave.

9.3.3 Minimum Standard - The two-signal selectivity curves shall not lie anywhere within the cross-hatched areas of Figures (4) and (5) respectively.

9.4 Spurious Response Attenuation

9.4.1 Definition - Spurious response attenuation is the ratio between the sensitivity to the desired signal and the sensitivity to any other signal.

9.4.2 Methods of Measurements

9.4.2.1 A3J - The sensitivity at the operating frequency shall be determined as outlined in Paragraph 9.1.2. The signal generator frequency shall then be varied from the lowest intermediate frequency to the 10th harmonic of the highest operating frequency of the receiver, excluding the frequency band covered by Fig. 5, and all responses shall be recorded. The ratio of the signal generator voltage required to produce a 12 dB SINAD ratio of any spurious response frequency to the signal generator voltage required to produce a 12 dB SINAD ratio at the operating frequency, expressed in dB, is the receiver's attenuation of the spurious response. The spurious response which required the least signal to produce a 12 dB SINAD ratio shall be used to express the receiver's spurious response attenuation.

9.4.2.2 A3/A3H - The tests under (a) above shall be repeated with receiver operating in the A3/A3H mode using the Standard Input Signal Source (B) and excluding the frequency band covered in Figure 5.

9.4.3 Minimum Standards - The spurious response attenuation shall be for:

Categories L, C, V -
60dB up to 10 MHz
50dB above 10 MHz
Category Y
40dB

9.5 Automatic Volume Control Characteristics

9.5.1 Definition - The automatic volume control characteristic is the variation of audio output as the radio frequency input level is varied over a specified range.

9.5.2 Methods of Measurement - Measurements are required on one test frequency only.

9.5.2.1 A3J Mode - Standard Input Signal Source (A) shall be connected to the receiver operating under standard test conditions and its frequency adjusted so that a 1000 Hz sinusoidal wave results at the receiver output. The receiver audio gain control shall be adjusted so that an input of 0.1 volt does not overload the audio section of the receiver. The audio output and distortion level shall then be noted as the input is varied from 30 micro-volts to 0.1 volt.

9.5.2.2 A3/A3H Mode - Standard Input Signal Source (B) shall be connected to the receiver operating under standard test conditions. The receiver audio gain control shall be adjusted so that an input of 0.1 volt does not overload the audio section of the receiver. The audio output and distortion level shall then be noted as the input is varied from 10 micro-volts to 0.1 volt.

9.5.3 Minimum Standards

9.5.3.1 Categories L, C, V - The audio power output shall not vary more than 10 dB and the distortion shall not exceed 15%. The signal shall be readable at 1 volt input.

9.5.3.2 Category Y - The audio distortion shall not exceed 25%. The signal shall be readable at 1 volt input.

9.6 Audio Power Output Rating

9.6.1 Definition - The audio power output rating is the maximum power output that the receiver can deliver without exceeding a specified distortion level.

9.6.2 Methods of Measurement - Measurements are required on one test frequency only.

9.6.2.1 A3J - A 1000 micro-volt signal from Standard Input Signal Source (A) shall be fed to the receiver. The audio power output shall be increased by means of the receiver gain control until the specified distortion level is obtained. This output level is the audio power output rating.

9.6.2.2 A3/A3H - A 1000 micro-volt signal from Standard Input Signal Source (B) shall be fed to the receiver. The audio power output shall be increased by means of the receiver gain control until the specified distortion level is obtained. This output level is the audio power output rating.

9.6.3 Minimum Standards

9.6.3.1 Categories L, C, V

  1. The audio power output rating of a receiver used to drive a loudspeaker shall be at least 2 watts at no more than 15% distortion.
  2. The audio power output rating of a receiver used to drive a headphone shall be at least 10 milliwatts at no more than 10% distortion.
  3. The audio power output rating of a receiver used to feed a line shall be at least 12 milliwatts at no more than 5% distortion.

9.6.3.2 Category Y - The manufacturer's specified audio power output, measured at no more than 15% distortion, shall be stated in the test report.

9.7 Intermodulation Distortion - This test is not required for Category Y equipment.

9.7.1 Definition - Intermodulation distortion is the measured value of spurious components appearing at the receiver output terminals under the test conditions below.

9.7.2 Method of Measurement - The input signal source shall comprise two equal amplitude radio frequency signals suitably combined, corresponding to (FD + 850 Hz) and (FD + 1950 Hz). The receiver shall be adjusted for operation on any selected datum frequency, and operated under standard test conditions and 50% of rated audio power output. The input signal to the receiver from each signal generator shall be simultaneously varied over the range 50 millivolts to 5 microvolts in 20 dB steps.

9.7.3 Minimum Standard - The level of any spurious product shall be at least 20 dB below the level of either of the two fundamental audio output signal over the input signal range 5 microvolts to 5 millivolts and shall be at least 15 dB below at an input of 50 millivolts.

9.8 Spurious Outputs

9.8.1 Definition - Spurious outputs are r.f. signals, generated within the receivers, which appear at the antenna terminals.

9.8.2 Methods of Measurement - The receiver shall be placed in operation at the standard test frequencies with the antenna terminals terminated with a nominal 50 ohm resistive load. Where other output terminations are used for the tests, they shall be specified in the test report and shall be within the impedance range of the equipment as stated by the manufacturer. The power of all significant spurious outputs shall be measured over the following frequency range.

  1. A low frequency limit equal to that of the lowest intermediate frequency or the lowest oscillator frequency in the receiver, whichever is the least.
  2. An upper frequency limit equal to 1000 MHz.

9.8.3 Minimum Standard - Spurious output at any discrete frequency shall not exceed 400 picowatts.

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10. Minimum Standards under Environmental Conditions (Receivers)

10.1 Tolerances - The maximum allowable tolerances on test conditions measurements shall be as follows:

  1. Temperature (degrees Centigrade): ± 3 degrees
  2. Voltage: ± 2 percent
  3. Humidity (relative): ± 5 percent

For the purpose of these tests, equipment temperature shall be considered stabilized when the temperature of the largest internal mass remains within ± 3°C of the specified environmental temperature when the equipment is inoperative or when the crest temperature of the largest internal mass does not vary more than ± 5°C with the equipment operating.

10.2 Measurements under Temperature and Voltage Extremes

10.2.1 Step 1: Low Temperature - Low Voltage - Category L and Y equipment shall be tested at 0°C. Category C and V equipment shall be tested at -20°C. Place the equipment in a chamber at the required low temperature and allow it to stand inoperative (i.e. without primary power supplied) until temperatures have stabilized. The receiver shall then have a warm-up period of thirty minutes under standby conditions. At the end of this period, the receiver shall be kept in operation in the chamber with the primary voltage decreased to 90% of standard test voltage.

  1. Frequency measurements shall then be recorded at one minute intervals for a five-minute period.
  2. The sensitivity shall be measured.

10.2.2 Step 2: Low Temperature - High Voltage - This test shall follow immediately after Step 1. The receiver shall be kept in operation with the primary voltage increased to 110% of standard test voltage.

  1. Frequency measurements shall then be recorded at one minute intervals for a five-minute period. (b)
  2. The sensitivity shall be measured.

10.2.3 Step 3: High Temperature - Low Voltage - Category Y equipment shall be tested at + 40°C Categories L, C, V at 50°C. With the equipment in the chamber at the required high temperature the receiver shall be operated for at least five hours. At the end of this period, the primary voltage shall be decreased to 90% of standard test voltage.

  1. Frequency measurements shall then be recorded at one minute intervals for a five-minutes period.
  2. The sensitivity shall be measured.

10.2.4 Step 4: High Temperature - High Voltage - This test shall follow immediately after Step 3. The receiver shall be kept in operation with the primary voltage increased to 110% of standard test voltage.

  1. Frequency measurements shall then be recorded at one minute intervals for a five-minute period. (b)
  2. The sensitivity shall be measured.

10.3 Measurements under Humidity Extremes - This test is required for Category "C" equipment only.

10.3.1 Step 1: The equipment shall be placed in the test chamber in a manner similar to that in which it will be used in service. The relative humidity shall be maintained in excess of 95% and the ambient temperature at ±40°C. The equipment shall remain in this atmosphere for a period if 8 hours. During this 8-hour period, no electrical or mechanical power shall be applied to the equipment.

10.3.2 Step 2: At the end of the 8-hour exposure period equipment shall be removed from the test chamber and any condensed moisture drained off. Within 5 minutes after removal, Standard Test Voltage shall be applied to the equipment. Thirty minutes shall be allowed, following application of primary power, for the equipment to warm up.

10.3.3 Step 3: Immediately following the 30 minute warm up period:

  1. The receiver frequency stability shall be recorded at one minute intervals for a five minute period.
  2. The sensitivity shall be measured.

10.4 Measurements under Vibration Conditions - This test is required for Category "C" equipment only. The equipment shall be secured to the vibration table through its normal attachments or mountings intended for use in service installations with vibration isolators, if any, in place. Additional straps or other holding means shall not be used. The equipment shall be mounted in the same position (with respect to the direction of gravity) for all vibration tests. Sinusoidal vibratory motion shall be applied to each of the three perpendicular axes of the equipment, i.e. lateral, vertical and longitudinal in any sequence under the following conditions:

  1. Constant total excursion of 0.030" from 10 to 30 Hz.
  2. The frequency shall change either linearly or logarithmically with time between 10 and 30 Hz such that a complete cycle (10-30-l0 Hz) will take approximately 5 minutes.
  3. The equipment shall be vibrated in each direction for a period of at least 30 minutes.

Throughout the vibration tests the equipment shall be operated according to the manufacturer's stated duty cycle and during the last five minutes of the test the frequency shall be recorded at one minute intervals and the sensitivity measured.

10.5 Minimum Standards under Environmental Conditions

10.5.1 All frequency measurements as recorded should be included in the test report. The recovered audio frequency shall not differ from the test frequency by more than

Category L
± 20 Hz
Categories C, V
± 60 Hz
Category Y
± 100 Hz

The receiver sensitivity shall not deteriorate more than 3 dB from the minimum standard specified under standard test conditions.

Issued under the authority of the
Minister of Communications

W.J. Wilson
Director
Telecommunications Regulation Branch

FIG-1 6.4.2.1 Spurious emission limits close to fundamental frequencies

Spurious emission limits close to fundamental frequencies (the long description is located below the image)
Description of Figure 1

Figure 1 shows the transmitter spurious emission limits. The x-axis represents the frequency offset from the channel frequency in kHz. The y-axis represents the power attenuation in dB.

FIG-2 6.5.3.1 Transmitter andio frequency response - categories L.C.V.

Transmitter andio frequency response - categories L.C.V. (the long description is located below the image)
Description of Figure 2

Figure 2 shows the transmitter audio frequency response for Categories LCV equipment. The x-axis represents the frequency offset from the channel frequency in kHz. The y-axis represents the power attenuation in dB.

FIG-3 6.5.3.2 Transmitter audio frequency response - category Y

Transmitter audio frequency response - category Y (the long description is located below the image)
Description of Figure 3

This figure illustrates that Industry Canada's three strategic outcomes—the Canadian marketplace

FIG-4 9.3.3 Receiver two-signal selectivity - A3J

Receiver two-signal selectivity - A3J (the long description is located below the image)
Description of Figure 4

Figure 4 shows the receiver two-signal selectivity for A3J equipment. The x-axis represents the frequency offset from the channel frequency in kHz. The y-axis represents the power attenuation in dB.

FIG-5 9.3.3 Receiver two-signal selectivity-A3H

Receiver two-signal selectivity-A3H (the long description is located below the image)
Description of Figure 5

Figure 5 shows the receiver two-signal selectivity for A3H equipment. The x-axis represents the frequency offset from the channel frequency in kHz. The y-axis represents the power attenuation in dB.


Amendment 1 to Radio Standards Specification (RSS) 181 Issue 1

This amendment clarifies the requirement for H3E emissions on the international distress frequency of 2182 kHz. All equipment operating on 2182 kHz must have the capability of transmitting and receiving H3E emissions (single sideband, full carrier) on that frequency. In addition, changes are made to update references.

The following changes are made to RSS 181 Issue 1:

  • Change the frequency range in the title from "1,605-28,00" to "1,605-28,000"
  • Delete paragraphs 3.1 and 3.2
  • Add new paragraphs 3.1 and 3.2 as follows:
    • 3.1 Radio Standards Procedure (RSP) 100 - Certification of Radio Equipment
    • 3.2 Radiocommunication Information Circular (RIC) 11- Implementation in Canada if Single Sideband Techniques in the Maritime Mobile Service.
  • Add new paragraphs 4.6 as follows:
    • 4.6 Requirements for Full Carrier Operation

      Equipment certified under this Specification that is intended to operate on 2182 kHz, must have the capability of operating in the full carrier H3E mode on the frequency 2182 kHz.

As of 1 January 1982 a new method for designating emissions came into force. The classes of emission found throughout RSS 181 are amended as follows:

RSS-181
OLD NEW
A3J J3E
A3H H3E
A3A R3E
A3/A3H A3E/H3E

The Department reserves the right to revise this amendment.

Effective Date: This amendment to RSS 181 Issue 1 is effective July 31, 1987.

Date modified: