MC5

MS5 (MS - “Ministry of Communications”) is a data transmission system and coded voice ( vocoder ) on standard single-band short-wave radio channels, as well as on multiplexing equipment (HF, RRL) channels in the frequency band from 300 to 3400 Hz , as well as 33 service formalized commands instead of basic information. For data transmission, BPSK (1200 bps) or QPSK (2400 bps) is used with a speed of manipulation of 120 characters per second per 12 orthogonal subcarriers (10 of which are intended to transmit user data) in the lower sideband. The distance between the subcarriers is 200 Hz, the frequency of the first subcarrier is 700 Hz. Also transmitted unmodulated pilot tone at a frequency of 3300 Hz (sometimes at 3600 Hz).

The standard is implemented in AT-3004D and AT-3104 equipment (has an additional mode with 20 subcarriers) produced by ALMAZ OJSC, as well as in CA147 packaging and CA266 product.

Amendments: 1. A laboratory sample of MS-5 equipment was prepared for testing at the Laboratory of Discrete Information Transfer of the Leningrad Electrotechnical Institute of Communications. prof. M.A. Bonch-Bruyevich. Head - prof. A. M. Zayezdny. From 1968 to 1972, the sample was tested on various HF radio paths. It was a 20 channel OFDM modem. The development and test results are reflected in the book mentioned in the list of references. Year of publication 1970. According to the results of the development of MS-5 in Kuibyshev dep. NIIRadio and Kiev Department. The ZNIIS Min. Communications of the USSR later made other, improved models of equipment, which were subsequently tested on long-distance radio telephone lines and data transmission lines. The modem provided a technical speed of 4800 bps in one sideband. Option mode - 3-fold FRM 6000 bps. The 2 .12-channel AT-3004D modem was developed at the Research Institute of Automation at the same time as the MS-5 as part of the same R & D. Its maximum performance is 2400 bps. The modem was transferred for serial production to NPO Almaz. Deliveries - the beginning of the 80s. 3. Pilot-signal in the equipment of wide application at the frequency of 3600 Hz is impossible, since the upper limit of the bandwidth is 3400 Hz.