IEC 60107-4:1999 pdf download – Recommended methods of measurementon receivers for television broadcasttransmissions – Part 4: Electrical measurements on multichannelsound television receivers using the two-carrier FM-system

IEC 60107-4:1999 pdf download – Recommended methods of measurementon receivers for television broadcasttransmissions – Part 4: Electrical measurements on multichannelsound television receivers using the two-carrier FM-system.
The methods ot measurement described in this standard apply to television receivers designed for the reception of television broadcast transmission using the two-carrier FMsystem. for the associated Sound (‘ITU-R Recommendation BS.707-3. annex 1).
2 Object
The object of this standard Is to standardize the methods of measurement for the more important electrical characteristics of receivers, within the scope of this part of the standard.
SECTION TWO — EXPLANATION OF TERMS
3 DefInition of modes
The two-carrier system otters the possibility of audio transmission using three different modes of operation:
dual sound; transmission of two independent sound signals stereophonic: transmission of a left and right channel sound signal monaural; transmission of a monaural signaL
4 Pilot signal
The pilot signal, which is transmitted on the second Sound carrier, enables the receiver to detect the mode of operation under which transmission takes place. For this purpose the following identification frequencies are modulated on an auxiliary carrier (pilot carrier):
5 IdentIfication signal modulation
Identification signal modulation denotes that modulation component of the second sound carrier which Is used to switch the decoder incorporated in the receiver into one of the three modes of operation.
6 Modes of operation
The following modes of operation are used for audio-reproduction.
6.1 Dual-sound mode
In the dual-sound mode, two independent monophonic sound signals are transmitted, It is possible to reproduce the signal of either channel alone, or those of both channels together.
The first Sound carrier transmits the audio signal which is compatible with monaural receivers. the second Sound carrier transmits the additional monaural signal.
6.2 StereophonIc mode
A stereophonic sound signal is reproduced in the stereophonic mode Here the first Sound
carrier transmits the compatible monaural signal while the second sound carrier transmits the
right channel signal. Both the left and the right channel signals are then restored by means of
a dematrixing circuit.
6.3 Monaural mode
In the monaural mode a monaural sound signal is reproduced by the receiver. The second sound carrier is modulated with the same monaural signal as the first sound carrier.
SECTION THREE —GENERAL NOTES ON MEASUREMENTS
7 General conditions
Unless otherwise stated, measurements shall be carried out under the conditions described in
IEC 60107-1 and IEC 60107-2.
8 Standard output power and voltage
8.1 Standard output power for loudspeaker
The standard output power shall be a power 10 dB below the rated output power (see 3.1 of IEC 60107-2). Alternatively, a stated, preferred value of output power, not directly related to the rated value, may be used; the peferred values are 500 mW. 50 mW and 5 mW. The corresponding levels are 27 dB(mW). 17 dB(mW) and 7 dB(mW). respectively. In all cases. the value chosen shall be stated with the results.
8.2 Standard line output voltage
The standard output voltage at a line output terminal shall be 500 mV r.m.s. at I kHz when terminated with a resistor equal to the rated load impedance.
9 Setting of tone controls
Unless otherwise specified, the tone controls or other controls that have an influence on the frequency response characteristics shall be adjusted for a practically flat response characteristic at the volume control position specified for the measurement. if the volume control Is physiologically weighted (loudness control) and the compensation cannot be switched off, ii shall be set foi’ minimum compensation effect and the reference output power obtained by adjusting the modulation Input level and this value stated with the results.
Switchable noise reduction and electronic base-widening circuits or the like shall be switched oft, if the tone controls are neither switchable nor adjustable, this shall be indicated with the results.
10 Setting of stereo balance control
For the balance setting. the receiver aerial input i provided with an ri. signal with
stereophonic identification. Both audio channels are modulated with 1 000 Hz and a
modulation factor of 30 %.
Unless otherwise specified, the balance control(s) shall be adjusted so that the output powers of the two channels are of the same value at the volume control position specified br measurement.