The Working Principle Of The Sweeper

The basic working process is to send 50Hz mains voltage down through the power transformer to the scanning sawtooth generator, forming a sawtooth wave. On the one hand, the sawtooth wave controls the sweeping signal generator and modulates the sweeping signal; on the other hand, the sawtooth wave is sent to the X-axis deflection amplifier to control the X-axis deflection plate of the oscilloscope and make the electron beam produce horizontal scanning. Since this sawtooth wave controls both the beam horizontal scanning and sweep oscillators, each horizontal position of the beam on the oscillotube screen corresponds to a certain instantaneous frequency. The frequency increases gradually from left to right, and the change is linear. The sweep signal generated by the sweep signal generator is sent to the broadband amplifier for amplification, sent to the attenuator, and then output the sweep signal to the measured circuit. In order to eliminate the parasitic amplitude modulation of the sweep signal, an automatic gain controller (AGC) is added to the wideband amplifier. The sweep signal output from the wideband amplifier is sent to a frequency label mixer where it is mixed with a 1MHz and 10MHz or 50MHz crystal signal or an external frequency label signal. The generated frequency signal is amplified by the Y-axis deflection amplifier and then output to the Y-axis deflection plate of the oscilloscope tube. After the sweep signal passes through the measured circuit, it is amplified by the Y-axis potentiometer, attenuator and amplifier and then sent to the Y-axis deflection plate of the oscilloscope tube, and the amplitude-frequency characteristic curve of the measured circuit is obtained.