| 摘要 |
A circuit for determining frequency response includes a voltage controlled oscillator (VCO) which generates a signal for application to a system under test and a counter which either counts quartz-stabilized pulses during a VCO period or which counts, during a quartz-stabilized counting interval, the VCO output itself. The counts represent with quartz accuracy the test frequency, which corresponds to the mean value within the counting interval, and are associated with respective measurement of signal level returned from the unit under test to thereby establish frequency response. Counts, together with corresponding levels developed by the system under test, are applied to a suitable display.
|
