Hey , I have tried a circuit with an MT8880 but the ICI has failed. I did hear the 16 tones, but when I wanted to receive them, the chip gave up the ghost. In theory I understand your suggestions well, but developing something like this is not easy for me. I'm just a LEGO builder. regards Hans
Op woensdag 23 februari 2022 om 19:30:37 UTC+1 schreef [email protected]: > Hi Hans, Kiste, > > You can still by DTMF decoders and I assume also DTMF encoders. Just look > at for example Aliexpress and type DTMF. > > But another suggestion. Many, many years ago I had built an Apple II and > I used cassette tapes to store and load games which was using tones > generated by the Apple II itself using two tones, one for high, one for low > and one as a lead-in tone (not sure in the lead-in tone was another tone) > to synchronze the start of the recorded program. You would not need this > lead-in tone in your case > > So I think it may not be that complex: > -) For recording on casette, generate this dual tone by the PIC via PWM > or maybe it is also sufficient to generate one tone in case of a 1 and no > tone in case of a 0 but I think this will be less reliable. > -) For playback, measure the length of the recorded PWM tone. If is is > within a certain range you accept it as a one and in case of two tones the > lower tone could be zero and the higher tone is one. > > As long as the tone frequency is not too high, I think this could work. > > A more advanced solution would be to use a phase locked loop (PLL) but I > am not sure if it will work. The PLL locks to the input signal so the > voltage that controls the oscillator goes up and down to follow (lock on > to) the input signal and this oscillator voltage signal could then be used > by a comparator of the PIC to detect a high or low tone. You can also use > the oscillator of the IC to generate the two tones by controlling the > oscillator voltage by the PIC. A typical IC for that is the HEF4046. I have > used this IC many many years ago too. This solution may be bit over the top > since you only want a kind of trigger signal > > But maybe the first solution is more doable. Just give it a try. > > Kind regards, > > Rob > > ------------------------------ > *Van:* 'Oliver Seitz' via jallib <[email protected]> > *Verzonden:* woensdag 23 februari 2022 09:58 > *Aan:* [email protected] <[email protected]> > *Onderwerp:* Re: [jallib] PWM serial audio transmission > > Hi Hans, > > 20 years ago I would have suggested using DTMF, but the decoder chips are > rare these days... > > PIC controllers include various peripherals which can be used to encode > and decode DC-free signals (which, apart from the frequency below, say, > 10kHz, is the requirement to be recorded as audio). On/off keying or > frequency shift keying are the easiest, I think. Which chips are you going > to use? > > Greets, > Kiste > > Am Mittwoch, 23. Februar 2022, 09:15:43 MEZ hat hans < > [email protected]> Folgendes geschrieben: > > > Hello everyone, > I have been trying for a long time to place a serial signal on one track > of an audio recording which I can read afterwards. To make all kinds of > things happen at the same time as the audio is played. I have now tried to > do this with the old modem system ( TCM3105) but it failed hopelessly. I > read that there are also systems to do this using PWM. Does anyone have an > idea? > regards > Hans > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/773ca37b-9bed-4349-a8eb-32a5d8973df6n%40googlegroups.com > > <https://groups.google.com/d/msgid/jallib/773ca37b-9bed-4349-a8eb-32a5d8973df6n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/201142693.752814.1645606718467%40mail.yahoo.com > > <https://groups.google.com/d/msgid/jallib/201142693.752814.1645606718467%40mail.yahoo.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "jallib" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jallib/94527fb5-d985-481c-b7c2-874c09a6286en%40googlegroups.com.
