| 摘要 |
radio communications; construction of radio receiving devices. SUBSTANCE: known method is based on processing input signal including automatic control of its output level in broad-band channel followed by converting signal in frequency conversion channel; then signal is processed with automatic control of its output level in narrow-band channel, and signals Uout.b and Uout.b arriving from outputs of broad-band and narrow-band channels, respectively, are measured. Novelty is that following interrelated procedures are involved: measurement of signal level Uin, at input of broad-band channel; comparison of Uin with maximum permissible input signal level Upmb 1; comparison of signal level Uout.b with maximum permissible level of output signal Upmb 2; comparison of signal level Uout.n with two threshold signal values corresponding to minimum and maximum threshold values Uth min and Uth max respectively; when Uin< Upmb 1 and Uout.n< Uth min,, input signal Uin is switched over directly to input of frequency conversion channel bypassing processing in broad-band channel; the latter procedure goes on until one of conditions, that is Uout.n> UH max or Uin>= Umpb 1, is satisfied; in other cases signal level Uout.b is automatically varied up to K.Uout.b when signal level Uout.b> Umpb 2; in this case factor K is found from condition K = (Umpb 2/Uout.b)-delta, where delta is stability factor; in addition, Uout.n measurement results are used for automatic control of signal level at output of narrow-band channel within desired range between Uth min and Uth max; in switching over broad-band channel from common channel gain factor of narrow-band channel is automatically changed by value proportional to broad-band channel gain for the period of excluding broad-band channel from common channel; in varying broad-band gain due to increase in Umpb 2 narrow-band gain is automatically continuously varied, in addition, by value inversely proportional to variations in K. EFFECT: enhanced sensitivity and noise immunity. 1 dwg
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