Sweep generator circuit for an electronic apparatus which produces a sweep signal having a sweep rate programmed by the settings of a selected plurality of controls of the electronic apparatus

摘要

Several current sources are provided which produce currents proportional to the logarithms of IF bandwidth, video bandwidth, and scan width of a spectrum analyzer. These currents are summed by an operational amplifier to produce a voltage proportional to the algebraic sum of these currents. This voltage is applied to an exponentiating transistor to produce a collector current which charges a capacitor whose voltage rise is linear with time. The voltage on the capacitor may be used as a sweep signal in a spectrum analyzer. Other circuits generate compensating voltages which are added to the aforementioned voltage applied to the exponentiating transitor to reduce variations in collector current due to temperature changes in this transitor.