The audio measuring equipment from LES Company

By Konstantin Shebzuhov

LES Company produces some modifications of the audio signal level indicators provided for application in editing and off-the-air control rooms for radio and TV broadcasting. The indicators allow to make the dynamic control of PPM level of signals and to display them visually. LEDs of various colors with large area of light emission and a wide angle of the view provide high reliability and convenience of the operator functioning.

Unit inputs may be configured or as high-resistance, operating “on pass”, or as low-resistance (600 Ohm). Reconfiguration is made by the switch on a back wall.

Top to bottom: the front panel of two-channel MS-21AS level meter, the front panel of two-channel MS-11AS level meter, the back panel of two-channel MS-21AS level meter

The modular multichannel indicator

LES Company indicators in central control room GCRT

At “on pass” application the indicator passes a signal without distortions, without dependence from absence or presence of a network supply.

Functionally the indicator corresponds to peak program meter of group II according to GOST 21185—75.

The basic models which are produced by LES, are two-channel MS-21AS and single-channel MS-11AS indicators of level of symmetric audio signals.

The features of indicators are the following:

• Reference level of input signals (adjustable) — -6…+10 dBm (initial — +4 dBm=1.26 V);
• Constant of time of the quasi-peak detector integration -10 ms;
• Maximum level of input signals — 10 V;
• Allowed overloads (at duration up to 5 microsecond) — up to 200 V;
• Number of indication steps — 19;
• Scale type — sectionally logarithmic;
• Range of measurements — -40…+3 dB;
• Working range of frequencies — 50 Hz…18 kHz.

Besides these two models the indicators with 16 and 20 channels in 3U case and modular version of the indicator are made for installation in the 3U basket. High reliability of indicators LES is confirmed with round-the-clock functioning in control rooms of State Central TV Center since 1996.

Material provided by LES-TV Company