Always heard that a telephone keypad generated square, sine and saw-tooth wave forms at different frequencies. Well, yeah it does and it does not. It will generate varying, unpredictable waveforms at differing frequencies, none stable. So a keypad, in my opinion, is NOT suitable for a reliable tone or signal generator. Now I am looking for a very small, sig-gen kit. Any ideas?
Karl
What frequency range and waveforms do you want to have?
Audio to start. Up to 1 mhz eventually.
Karl
The telephone keypad (DTMF) generates a pair of sinewave tones for each key press. That is why it looks strange. No square or sawtooth available from a typical DTMF generator.
This may not be what you’re after, but a PC (using the sound card) can generate excellent test waveforms in the audio range. I have a copy of Nero WaveEdit which can do sinus, saw-tooth, square, decay, attack, noise, mix and what not. A Google search will probably give you lots of alternative software’s and probably a number of free ones as well.
Perhaps you can find this projects of some interest:
http://www.electronics-lab.com/projects/test/013/index.html
http://www.scienceprog.com/avr-dds-signal-generator-v20/
BenF put me on the trail and I found NCH which has a very simple tone generator with all waveforms available! Gotta be simple if I can download and operate successfully! Thanks again!
Karl
Well, I DID get it loaded on to the 'puter and it seemed to work different tones and different sounds for sine, square, etc. HOWEVER, when hooked up to nano, the wave forms had a lot of noise. Is that the computer trashing the signal?
Karl
I forgot to thank lygra for the DTMF telephone tone gen info. Thanks, lygra!
Karl