I'm want to build a project which outputs DTFM tones like a telephone. I looked at different oscillator circuits like the wein to create clean sine waves for each tone but still investigating. There are a few parts which already do DTFM tone generation like HT9200A but I wanted to design my own similar oscillator circuit. I'm aiming to create as clean a DTFM signal as possible, with low total harmonic distortion.
Basically, I want to build a circuit that duplicates what HT9200A does as far as tone generation. Here is the datasheet: https://pdf1.alldatasheet.com/datasheet-pdf/view/64509/HOLTEK/HT9200A.html
I looked at using an RC type oscillator to generate each tone, but not sure I can get the exact frequencies ( or within 0.6% ) I need for DTFM. Capacitor and Inductor based oscillator circuits have inaccurate tolerances so I'm looking at a resistor based oscillator. The HT9200A part uses a 3.58MHz crystal to get about 0.6% accuracy for frequencies, but I require a few additional frequencies generated.
The following frequencies need to be generated:
120Hz, 350Hz, 440Hz, 600Hz, 697Hz, 770Hz, 852Hz, 941Hz, 1209Hz, 1336Hz, 1477Hz, 1633Hz, 2400Hz, 3600Hz
UPDATE: I should have mentioned I require an analog output signal, and not digital.
Thank you!!
Basically, I want to build a circuit that duplicates what HT9200A does as far as tone generation. Here is the datasheet: https://pdf1.alldatasheet.com/datasheet-pdf/view/64509/HOLTEK/HT9200A.html
I looked at using an RC type oscillator to generate each tone, but not sure I can get the exact frequencies ( or within 0.6% ) I need for DTFM. Capacitor and Inductor based oscillator circuits have inaccurate tolerances so I'm looking at a resistor based oscillator. The HT9200A part uses a 3.58MHz crystal to get about 0.6% accuracy for frequencies, but I require a few additional frequencies generated.
The following frequencies need to be generated:
120Hz, 350Hz, 440Hz, 600Hz, 697Hz, 770Hz, 852Hz, 941Hz, 1209Hz, 1336Hz, 1477Hz, 1633Hz, 2400Hz, 3600Hz
UPDATE: I should have mentioned I require an analog output signal, and not digital.
Thank you!!
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