| 摘要 |
FIELD: analog multichannel frequency-division multiplex telephone communication systems; development and manufacture of terminal transceiving equipment of cable and radio-relay telephone lines, such as organization of rural communication lines. SUBSTANCE: system has driving and driven sets of terminal transceiving equipment of telephone trunk coupled through line channel; each set of equipment has matching differential amplifiers, frequency synthesizer, channel modulators and demodulators, low-frequency filters, modulated signal adder and power splitter, transmitting and receiving device of line channel; channel modulators and demodulators of system are, essentially, two-balance multipliers; driving set has reference-frequency crystal oscillator and frequency synthesizer that shapes coherent channel subcarriers and pilot- signal spectrum; driven set has device shaping reference frequency coherent with driving-set reference frequency from pilot-signal. EFFECT: improved functional reliability due to elimination of cross-talk interchannel noise, reduced mass and size of equipment, reduced manufacturing and maintenance cost. |
