IEC 61305-2:1997 pdf download.Household high-fidelity audio equipment and systems – Methods of measuring and specifying the performance
1 General
1.1 Scope
This part of IEC 61 305 applies to household high-fidelity radio tuner units with facilities for reception of frequency modulation sound broadcasts with a rated maximum system deviation of ±75 kHz, using the pilot-tone system for stereophonic broadcasting (see ITU-R BS.450-2). It may be applied to systems using a rated maximum system deviation of ±50 kHz by decreasing all the stated deviations in proportion. It also applies, except where stated, to equipment having multiple functions, including these facilities. It is intended to be read in conjunction with part 1 of this standard.
1.2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of IEC 61 305. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this part of IEC 61 305 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
IEC 6031 5-1 :1 988, Methods of measurement on radio receivers for various classes of emission
– Part 1 : General considerations and methods of measurement, including audio-frequency
measurements
IEC 6031 5-4: , Methods of measurement on radio receivers for various classes of emission –
Part 4: Receivers for frequency-modulated sound broadcasting emissions 1 )
ITU-R BS.41 2-7:1 995, Planning standards for FM sound broadcasting at VHF
ITU-R BS.450-2:1 995, Transmission standards for FM sound broadcasting at VHF
ITU-R BS.641 :1 986, Determination of radio-frequency protection ratios for frequency modulated sound broadcasting
ITU-R BS.704:1 990, Characteristics of FM sound broadcasting reference receivers for planning
purposes
1.3 Conditions for measurement
1.3.1 Electrical conditions Except where stated, the electrical conditions shall be those specified in IEC 6031 5-1 and IEC 6031 5-4, and measurements shall be made at a radio-frequency input level of 70 dB (fW), equivalent to an e.m.f. source of 1 ,7 mV in a 75 & system. Measurements of output shall be made at the main output terminals of the equipment, and the terminals used shall be stated with the results. If an output level control is provided (other than as a factory preset), it shall be set at a fixed position, stated with the results, within the range of settings to be expected in use.
1.3.2 Climatic conditions
See 2.2 of part 1 .
1.4 Reference audio-frequency output level
Except where stated, the 0 dB reference level for all a.f. output voltage measurements
expressed in decibels shall be the a.f. output voltage produced by an r.f. input signal level of
70 dB (fW), modulated at 1 kHz with ±67,5 kHz deviation; for a stereo signal the channels are
modulated in phase.
2.1 Noise-limited sensitivity at 50 dB signal- to-noise ratio, expressed as the input signal level in dB (fW). 2.2 Effective frequency range expressed as the range over which the response does not vary by more than ±1 ,5 dB from the level at 1 kHz (see 1 .4). 2.3 Interchannel gain difference expressed as the maximum difference in level of the right channel output with respect to that of the left channel output, in decibels, over the frequency range 250 Hz to 6,3 kHz.
According to 5.2 of IEC 60315-4, with an r.f. input signal level of 70 dB(fW), a modulation frequency of 1 kHz and a deviation of +67 ,5 kHz, except where otherwise stated. The equipment shall be in the stereo mode. NOTE – To ensure that distortion measurements are not invalidated by noise, at each stage the output obtained with an unmodulated carrier should be noted. Measurements of distortion components are valid only if at least 10 dB higher than the noise level.
IEC 61305-2:1997 pdf download
