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IFD:Printing Acoustic Interfaces/acoustic sensing circuits (view source)
Revision as of 20:01, 27 June 2019
, 27 June 2019→Printed Capacitive (Condenser) Microphone
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[[File:receiving_circuit.png| thumb| left| receiving circuit]] | [[File:receiving_circuit.png| thumb| left| receiving circuit]] | ||
The receiving capacitor plate's capacity is modulated by the high frequency triangle wave from the first plate, as well as the distance from this first plate. The distance modulation in audio range (0-20kHz) is what we are interested in detecting. First we pre-amplify the modulated signal from the receiving capacitor plate with a charge mode amplifier, than we detect the envelope of the high frequency wave with a half wave rectifier and a low pass filter and finally amplify and buffer the resulting envelope. The output of this receiver circuit corresponds to the distance of the two capacitor plates in audio rate, the signal we were originally interested to detect. | The receiving capacitor plate's capacity is modulated by the high frequency triangle wave from the first plate, as well as the distance from this first plate. The distance modulation in audio range (0-20kHz) is what we are interested in detecting. First we pre-amplify the modulated signal from the receiving capacitor plate with a charge mode amplifier, than we detect the envelope of the high frequency wave with a half wave rectifier and a low pass filter and finally amplify and buffer the resulting envelope. The output of this receiver circuit corresponds to the distance of the two capacitor plates in audio rate, the signal we were originally interested to detect. | ||
The following two diagrams show the breadboarded sending and receiving circuits using two TL072's or one TL074. Note that instead of four AA batteries we are using two 9V blocks two get a dual power supply of +-9V. | |||
[[File:microphone_amp_tl072_Steckplatine.png | thumb|left| TL072 Version ]] | [[File:microphone_amp_tl072_Steckplatine.png | thumb|left| TL072 Version ]] | ||