| 摘要 |
PURPOSE:To ensure generation of the marker of an accurate frequency by using the memory unit. CONSTITUTION:The frequency sweep is started from T2 of sweep transmission gate signal 21 via sweep oscillator (output terminal 2). At the same time, the voltage of sweep-use saw-tooth wave 22 of input terminal 12 rises up gradually from T2. When this voltage becomes at same the level as the voltage of analog memory 17-1, comparator 13 transmits the output signal. And start signal generator 14 actuates preset counter 9 and reference gate signal oscillator 11 via start signal 23. The reference time produced through generator 11 is set to 1m sec., and counter 9 counts the number set to frequency setting unit 10-1 (counting time 24) per K Hz. Thus, comparator 15 lowers the voltage of memory 17-1 if the counting time is shorter than reference time 1m sec. and hightens the voltage if the counting time is longer than the reference time respectively. And in case the counting time is identical to the refernce time, it is decided that the frequency of the sweep sighal has cioncided with the frequency set (10-1). Thus, accurate marker signal 25 is generated. |
