grandestlama
New Member
Hello,
I have designed a waveform display program to act as an oscilloscope for home use that can handle electrical signals from circuits when these signals are fed into the soundcard .
I first have to bring down signal voltages to a safe level of about 1 - 2V (AC). I have done this using a voltage divider arrangement.
when I feed this voltage to the soundcard (microphone port), no output is displayed. When i connect a microphone however and speak into it, a waveform is displayed. In addition I wrote a function generator (sine, square etc), and when this program is ran, if its output collected from the "speaker out" port (on the soundcard) is fed into the "microphone in" port (on the soundcard) it is correctly plotted on the display program.
I measured the output voltage from microphones, it is about 1 - 2 v so I am wondering why the 1V from microphones show a waveform whereas the 1 - 2V from external circuits does not. I guess this is an impedance matching problem, but I am not sure of what to do further. I would like to know how to make my signal compatible with that from the microphes so that it can be plotted too. Any idea is appreciated ! Thanks .
I have designed a waveform display program to act as an oscilloscope for home use that can handle electrical signals from circuits when these signals are fed into the soundcard .
I first have to bring down signal voltages to a safe level of about 1 - 2V (AC). I have done this using a voltage divider arrangement.
when I feed this voltage to the soundcard (microphone port), no output is displayed. When i connect a microphone however and speak into it, a waveform is displayed. In addition I wrote a function generator (sine, square etc), and when this program is ran, if its output collected from the "speaker out" port (on the soundcard) is fed into the "microphone in" port (on the soundcard) it is correctly plotted on the display program.
I measured the output voltage from microphones, it is about 1 - 2 v so I am wondering why the 1V from microphones show a waveform whereas the 1 - 2V from external circuits does not. I guess this is an impedance matching problem, but I am not sure of what to do further. I would like to know how to make my signal compatible with that from the microphes so that it can be plotted too. Any idea is appreciated ! Thanks .