| 摘要 |
<p>PURPOSE:To make an output amplitude constant by providing storage areas corresponding to pulses of order constituting a burst signal and specifying corresponding storage area every time an input pulse of order arrives at an address specifying circuit. CONSTITUTION:This circuit is constituted only as shown in a figure where an address specifying circuit 3 and storage areas 41 as many as pulses in the burst are provided, and consequently the circuit operates as if cyclic low-pass filters as many as the pulses in the burst signal were provided. Then, variation in the amplitude of a pulse train proportional to the crest value of a detection pulse train to an adder 2, i.e. high-frequency transmission pulse train is filtered according to low-pass filtering characteristics and appears at the output of the 2nd multiplier in the order of the pulses in the burst signal. Namely, the circuit performs automatic gain control in which negative feedback is provided so that the amplitude of the high-frequency transmission pulses is constant. Consequently, a complex function circuit need not be used to correct a sag phenomenon accurately, and there is no problem due to variation in temperature or source voltage in this case.</p> |
