M72 音响、电声设备 标准查询与下载

ITU-T J.19-1988 用于测量其他通道中的干扰的模拟声音节目信号的常规测试信号

ITU-T Recommendation J.19 was published in Fascicle III.6 of the Blue Book. This file is an extract from the Blue Book.While the presentation and layout of the text might be slightly different from the Blue Book version,the contents of the file are identical to the Blue Book version and copyright conditions remain unchanged (see below).

A CONVENTIONAL TEST SIGNAL SIMULATING SOUND - PROGRAMME SIGNALS FOR MEASURING INTERFERENCE IN OTHER CHANNELS

ITU-T J.13 SPANISH-1988 国际声音程序电路的定义.非电话信号的线路传输.声音程序和电视信号的传输(研究组15)3页

Definitions for international sound-programme circuits

ITU-T J.13 FRENCH-1988 国际声音程序电路的定义.非电话信号的线路传输.声音程序和电视信号的传输(研究组15)3页

Definitions for international sound-programme circuits

ITU-T J.13-1988 国际声音程序电路的定义.非电话信号的线路传输.声音程序和电视信号的传输(研究组15)3页

Definitions for International Sound-Programme Circuits - Line Transmission of Non-Telephone Signals - Transmission of Sound-Programme and Television Signals (Study Group XV) 3 pp

IEC 60268-1:1985/AMD1:1988 声系统设备 第1部分:总则 修改1

This amendment refers to page 31 of IEC 268-1 and the replacement of Table AII.

Sound system equipment. Part 1: General

ITU-T P.76 SPANISH-1988 响度评定值的测定.基本原理

A speech path is, broadly, a transmission path that exists between a talker’s mouth and the ear of a listener or, in the case of sidetone, between the mouth and ear of a talker. In typical face-to-face conversation, the speech is transmitted by means of the air path connecting the mouth and ear.

DETERMINATION OF LOUDNESS RATINGS; FUNDAMENTAL PRINCIPLES

ITU-T P.76 FRENCH-1988 响度评定值的测定.基本原理

A speech path is, broadly, a transmission path that exists between a talker’s mouth and the ear of a listener or, in the case of sidetone, between the mouth and ear of a talker. In typical face-to-face conversation, the speech is transmitted by means of the air path connecting the mouth and ear.

DETERMINATION OF LOUDNESS RATINGS; FUNDAMENTAL PRINCIPLES

ITU-T P.61 SPANISH-1988 电容器传声器的校准方法

The recommended procedure for primary calibration of condenser microphones is the reciprocity calibration technique. A precision method for reciprocity pressure calibration is described in [1]. A simplified method, suitable for calibration over the frequency range of interest for telephonometric measurements, is given in [2]. Although the methods described are specifically for one-inch microphones, similar methods are applicable to half-inch microphones. Methods suitable for half-inch microphones are under study by IEC.

METHODS FOR THE CALIBRATION OF CONDENSER MICROPHONES

ITU-T P.61 FRENCH-1988 电容器传声器的校准方法

The recommended procedure for primary calibration of condenser microphones is the reciprocity calibration technique. A precision method for reciprocity pressure calibration is described in [1]. A simplified method, suitable for calibration over the frequency range of interest for telephonometric measurements, is given in [2]. Although the methods described are specifically for one-inch microphones, similar methods are applicable to half-inch microphones. Methods suitable for half-inch microphones are under study by IEC.

METHODS FOR THE CALIBRATION OF CONDENSER MICROPHONES

ITU-T P.54 SPANISH-1988 声级计(客观测量室内噪声的仪器)

The CCITT recommends the adoption of the sound level meter specified in [1] in conjunction, for most uses,with the octave, half, and third octave filters in accordance with [2].

SOUND LEVEL METERS (APPARATUS FOR THE OBJECTIVE MEASUREMENT OF ROOM NOISE)

ITU-T P.54 FRENCH-1988 声级计(客观测量室内噪声的仪器)

The CCITT recommends the adoption of the sound level meter specified in [1] in conjunction, for most uses,with the octave, half, and third octave filters in accordance with [2].

SOUND LEVEL METERS (APPARATUS FOR THE OBJECTIVE MEASUREMENT OF ROOM NOISE)

ITU-T O.132 SPANISH-1988 使用正弦信号测试的量化失真测量设备

This specification gives basic clauses describing the essential features to be provided in test equipment using a sinusoidal test signal for quantizing distortion measurements on PCM channels. It is important that the characteristics of quantizing distortion measuring apparatus of this type are sufficiently specified to ensure that they are capable of interworking and that they will give results of sufficient accuracy. This specification is based on a general statement of the method described as Method 2 in § 9 of Recommendation G.712 [1].

QUANTIZING DISTORTION MEASURING EQUIPMENT USING A SINUSOIDAL TEST SIGNAL

ITU-T O.131 SPANISH-1988 使用伪随机噪声测试信号的量化失真测试设备

It is important that the characteristics of quantizing distortion measuring apparatus are specified with sufficient precision to ensure that all future designs of measuring apparatus conforming to the recommended specification shall be compatible with one another, i.e., they shall be capable of interworking and give results of specified accuracy without the need for any special procedures or corrections to the measurements results. It is considered equally important that all designs of measuring apparatus conforming to the recommended specification shall be capable of interworking with existing designs of measuring apparatus already in use by various Administrations, who will thus not be placed at any economic disadvantage. The following specification is based on the proposals studied by Study Group XVIII and is specifically aimed at the foregoing compatibility objectives.

QUANTIZING DISTORTION MEASURING EQUIPMENT USING A PSEUDO-RANDOM NOISE TEST SIGNAL

ITU-T O.27 FRENCH-1988 站内回声抵消器测试设备

The in-station echo canceller test equipment (ISET) is intended to test type C and D echo cancellers including tone disablers as specified in Recommendation G.165 [1]. Two test modes are provided as described below. The tests performed in each test mode are listed in Table 1/O.27.

In-Station Echo Canceller Test Equipment

ITU-T J.23-1988 7kHz类型(窄带)声音节目电路的性能

ITU-T Recommendation J.23 was published in Fascicle III.6 of the Blue Book. This file is an extract from the Blue Book.While the presentation and layout of the text might be slightly different from the Blue Book version,the contents of the file are identical to the Blue Book version and copyright conditions remain unchanged.

PERFORMANCE CHARACTERISTICS OF 7 kHz TYPE (NARROW-BANDWIDTH) SOUND - PROGRAMME CIRCUITS

ITU-T J.18-1988 电缆电视系统的数字节目插入提示消息

This Recommendation outlines the principles followed by the CCITT in determining what limits are appropriately set for sources of crosstalk affecting sound-programme circuits and other principles which Administrations might apply to ensure that the objectives for intelligible crosstalk in sound-programme circuits are achieved in practice.

CROSSTALK IN SOUND - PROGRAMME CIRCUITS SET UP ON CARRIER SYSTEMS

ITU-T J.17-1988 用于声音节目传输电路的预加重

The noise spectrum in group links is usually uniformly distributed, i.e. all parts of the frequency band are equally disturbed by the noise signal. Sound-programme signals, on the other hand,are not of uniform distribution.The mean power density of the signals tends to decrease towards higher frequencies.Furthermore,the sensitivity of the receiving part (consisting of the radio receiver, the loudspeaker and the human ear) in respect of noise is very dependent on the frequency.(This can be seen from the psophometric weighting curve which is a measure of the sensitivity of the complete receiving part.)

PRE - EMPHASIS USED ON SOUND - PROGRAMME CIRCUITS

ITU-T J.16-1988 声音节目电路中加权噪声的测量

The noise objectives for sound-programme circuits are defined in terms of psophometrically weighted noise power levels at a zero relative level point.Psophometric weighting is used to ensure that the objectives and the results of measurements are directly related to the disturbing effect of the noise on the human ear.The psophometric weighting for sound-programme circuits consists of two operations:? a frequency-dependent weighting of the noise signal,and ? a weighting of the time function of the noise signal to take account of the disturbing effect of noise peaks.

Measurement of Weighted Noise in Sound - Programme Circuits

ITU-T J.15-1988 数字多节目电视、声音和数据业务通过多路多点分配系统(MMDS)传送的操作功能

This test signal is based on the test signal definitions given in CCIR Recommendation 645 and specifies a test signal which should be used on sound-programme circuits generally. A common alignment procedure for peak programme meters and VU-meters using the three-level test signal can be found in Annex I of CCIR Recommendation 645. From this information it can be seen what indicators will be produced by the three-level test signal on the different types of peak programme meters and volume meters.

Lining - up and Monitoring an International Sound - Programme Connection

ITU-T J.14-1988 数字电缆电视系统的图像主观质量评价

The CCITT recommends the use of the constant voltage method. If, to a zero relative level point of the international sound-programme connection,a zero absolute voltage level is applied (sine-wave signal of 0.775 volts r.m.s.) at the reference frequency 0.8 or 1 kHz, the absolute voltage level at the output of each sound-programme circuit (Points B, C, D . . . F of Figure 3/J.13) should be + 6 dB (i.e. 1.55 volts r.m.s.).Therefore these points have to be regarded as relative level points of + 6 dBrs according to Recommendations J.21, J.22 and J.23.

RELATIVE LEVELS AND IMPEDANCES ON AN INTERNATIONAL SOUND - PROGRAMME CONNECTION