I tried to interface a FM multiplex signal through an transistor amplifier to ADC.Then I tried to convert the sampled signal to an analog signal and observed the output through oscilloscope. But the observed output was distorted. Then I give a 400mV signal from signal generator and amplified it to 5V. The amplified signal is then given to the ADC observed the DAC output.But the observed output is distorted. But when I give the 5v sinusoidal signal from signal generator directly to the ADC and observe the DAC output,Then I can observe a waveform similar to the input. 1)I think there is a issue with the amplifier's output impedance. Is my assumption correct? 2)How to overcome this problem? (since the FM mux output is 500mV I need to use an amplifier) 3)How to increase the amplifiers output impedance?
: Edited by User
Here is the circuit I had tested(img 1). When I give an analog signal I can get the emitter follower output as follows. (Yellow - output , Blue -input)(img 2) After giving the emitter follower output to the ADC and observe the DAC output from oscilloscope,I can observe a distorted signal as follows(yellow). (img 3) How to get the original signal from the ADC? What are the modifications I need to do?