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BETS-4 — Technical Standards and Requirements for Television Broadcasting Transmitters

Technical Standards and Requirements for Television Broadcasting Transmitters
(PDF, 1323 KB, 50 pages)

Issue 1
November 1st 1996

Broadcasting Equipment Technical Standard

Purpose

This document contains the technical standards and requirements for the issuance of a Technical Acceptance Certificate (TAC) for television broadcasting transmitters.

A certificate issued for equipment classified as type approved or as technically acceptable before the coming into force of these technical standards and requirements is considered to be a valid and subsisting TAC.

A Technical Acceptance Certificate is not required for equipment manufactured or imported solely for re-export, prototyping, demonstration, exhibition or testing purposes.

Table of Contents

  1. General
  2. Testing and Labelling
  3. Standard Test Conditions
  4. Transmitting Equipment Standards
  5. Equipment Requirements
  6. RF Emission Standards

1. General

1.1 The standards and requirements in this document are the pre-requisite conditions for the issuance of a Technical Acceptance Certificate (TAC) for television broadcasting transmitters.

1.2 Those seeking to obtain a Technical Acceptance Certificate for television transmitters shall, at their own expense, carry out the required tests and send to the Department a certification submission and an engineering brief prepared in accordance with Broadcasting Equipment Standards Procedure 100 (BESP- 100).

1.3 The engineering brief, signed by a professional engineer licensed by a provincial association, shall demonstrate that the equipment meets the technical standards in this document.

1.4 Notwithstanding the fact that a radio apparatus meets all applicable requirements, the Department reserves the right to require that adjustments be made to the equipment should it cause interference.

1.5 Any major design or component changes, other than the replacement of defective components by equivalent parts, will void the approval unless notified to and approved by the Department.

1.6 This document replaces RSS-154, Issue 3.

2. Testing and Labelling

2.1 Section 3 to 6 contain the general equipment standards and the minimum emission standards which relate to the radiated signal of the TV transmitting equipment. Compliance to the standards of these sections shall be supported by an engineering brief stating measurement results in accordance with Broadcasting Standards Procedure 100 (BSP 100).

2.2 Annex A contains the performance standards recognized by the industry to ensure quality operation of TV broadcasting equipment. Compliance to the standards of Annex A shall be supported by a statement certifying that the equipment meets the standards. The submission of test results for performance measurements is not required but the results shall be kept on file by the applicant.

2.3 This document covers the transmitting equipment proper: namely from the video and audio input terminals or the RF input terminal to the output terminals including the filters and the diplexer supplied with the transmitting equipment.

2.4 Equipment considered as low power TV broadcasting transmitting units is classified under one of the following categories:

Category A

Low power equipment designed to operate in a varying temperature environment.

Category B

Low power equipment designed to operate in a controlled temperature environment.

2.5 In the event that the equipment fails to function during the certification tests, all tests affected by the failure shall be repeated after the fault has been corrected.

2.6 The transmitting equipment shall be capable of meeting the standards in this document on each channel at the rated power output for which it is designed to operate. (See also 6.1.4.)

2.7 Each certified broadcasting equipment must display in a conspicuous location:

  1. The manufacturer's name, trade or brand name (if different from the manufacturer's name)
  2. The model identification
  3. The serial number
  4. The Technical Acceptance Certificate number
  5. The certificate number for low power equipment shall be suffixed with the appropriate category designator (See 2.4).
  6. The name of the certification assignee

2.8 The identification label must be indelible, tamper-resistant and affixed permanently or stamped in such a manner as not to be removable except by destruction or defacing.

3. Standard Test Conditions

3.1 Definition

Standard test conditions are those conditions which shall apply to a transmitting equipment while it is being tested for minimum requirements. These conditions apply unless otherwise specified. Where no special conditions are called for in the tests, the conditions shall be those specified by the manufacturer for normal operation, and these shall be stated in the engineering brief.

3.2 Standard Test Voltage

Shall be one of the rated power supply voltages specified by the manufacturer.

3.3 Standard Temperature

Shall be no less than 20° C. Actual temperature shall be recorded in the engineering brief.

3.4 Standard Test Load

Shall consist of an impedance of substantially zero reactance and a resistance equal to the surge impedance of the load into which the equipment is designed to operate. The test load impedance shall be essentially constant over the band of frequencies being considered with a return loss of 32 dB minimum, 1.05:1 or better voltage standing wave ratio (VSWR) over the operating channel.

3.5 Standard Test Frequency

Shall be the visual and aural carrier frequencies of the channel for which the equipment is designed to operate. For equipment capable of operating on one of several channels, tests shall be made on one channel in each band.

3.6 Standard Test Input Signals

3.6.1 The standard video test input signal shall be in accordance with the standard television signal as specified for system M/NTSC (see Appendix A), and shall have a peak-to-peak amplitude of 1.0 volt, (140 IRE units). The polarity of the signal shall be black negative. The voltage shall be measured across the input terminals.

3.6.2 The standard aural test signal shall be a 400 Hz sine wave.

3.6.3 The standard RF test signal shall be the standard television signal as specified for system N/NTSC (see Appendix A). The RF input signal for the translator shall be derived from a test modulator and shall occupy a band of spectrum which coincides with a standard designated television channel. The signal shall contain simultaneously a visual carrier modulated with a video waveform consisting of sync, blanking and picture signal as appropriate for the test and an unmodulated aural carrier at a level 10 dB below the peak visual carrier. Unless otherwise specified, the level of the RF input signal shall be 1 mVrms (0 dBmV).

3.7 Standard Test Equipment

All measurements shall be made with test instruments of accuracy sufficient to ensure that no appreciable error due to test equipment is introduced in the results.

3.8 Standard Test Set-up

3.8.1 Internally Diplexed Transmitting Equipment

Unless stated otherwise, all visual tests shall be made with the unmodulated aural carrier present at rated power output and all aural tests shall be made with a visual carrier present, at the rated power output and modulated with a staircase video waveform of 50% average picture level (APL). For tests requiring a demodulated video output, a test demodulator with appropriate display devices or metres shall be used.

3.8.2 Externally Diplexed Transmitting Equipment

3.8.2.1 The standard test load shall be connected to the output of the diplexer and tests carried out with one transmitter on at a time. For tests requiring a demodulated output the same monitoring equipment shall be used as for internally diplexed equipment.

3.8.2.2 Unless otherwise stated, all tests shall be performed with the harmonic filters and the external diplexer connected between the transmitters and the sampling point for the test concerned.

3.8.3 Translating Equipment

The standard test load shall be connected to the output of the translator (see definition in 4.1.3) and tests carried out with the test signal supplied from the test modulator unless specified otherwise. For tests requiring an demodulated output, the same monitoring equipment shall be used as for internally diplexed equipment.

3.9 Warm-up Time

The transmitting equipment and test equipment shall be switched on at least 30 minutes before any test is started.

4. Transmitting Equipment Standards

4.1 Definitions

4.1.1 Transmission System

A television transmitting system consists of the apparatus necessary to convert the input signals to standard output signals as specified in television system M/NTSC. (See Appendix A)

4.1.2 Transmitter

A television transmitter consists of the apparatus necessary to convert the standard video and audio input test signals to the standard television output signal as specified for television system M/NTSC. (See Appendix A)

4.1.3 Translator

A television translator consists of the apparatus necessary to convert a standard RF television input signal to the standard television output signal as specified for television system M/NTSC. (See Appendix A)

4.1.4 Low Power Transmitting Equipment

A television transmitter or translator having a maximum power output of 50 watts on VHF channels and 500 watts on UHF channels, and is designed to be operated under the requirements for low power television broadcasting stations under one of the following categories of operating conditions:

Category A

Equipment designed to operate in a varying temperature environment.

Category B

Equipment designed to operate in a controlled temperature environment.

The appropriate category designation will be suffixed to the certificate number.

4.2 Type of Emission

Visual transmission shall employ vestigial sideband amplitude modulation and aural transmission shall employ frequency modulation.

4.3 Power Output Rating

The power output rating of a television transmitting equipment is that of the visual transmission section.

4.4 Audio Pre-emphasis

The audio signal shall be pre-emphasized in accordance with a 75 microsecond pre-emphasis curve. (See Appendix B)

4.5 Power Supply Rating

The preferred AC voltage input ratings are 120/240 V single phase, 120/208 V three phase, or 480 V three-phase, at a frequency of 60 Hz. Voltage, frequency, maximum kVA rating, and power factor shall be indicated on the equipment.

4.6 Phase-to-Phase Loading

The equipment, if rated above 10 kVA input, shall present a balanced load to the AC mains such that the current in each phase shall be balanced within 10% of the average of the three currents.

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