LDR Optocoupler Hi-Fi Attenuator - Technical Data & Laboratory Tests

Frequency Response Test

The frequency response at maximum volume for 01 Hz - 24 kHz, bear in mind that LDRs cannot achieve a full 0 dB attenuation (lossless) because the LDR possess a minimal resistance even when fully lit, in this case, the maximum volume is of -1.9 dB. We can see that the peak line is linear with no noticeable variations, the testing device is calibrated till 20 kHz, therefore, a slight drop at the end of the spectrum is to be expected. 

The frequency response at -24 dB attenuation. In this screen, we can see that the spectrogram detected slightly higher harmonic distortion than at full volume.

The frequency response at -48 dB attenuation, the frequency response continues to be flat.