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Silver Sabre Plus
Interesting that Silver Sabre plus seems to work at +5 volts, not +8 like TGS.
Also, wonder why they did not use TX signal as oscillator for ICL 7660 negative supply, to reduce chance of interference from another oscillator? Maybe because not rated well above 10kHz.
Perhaps related to other interesting feature which is that the ICL 7660 appears to generate the tone for the audio circuit, unlike the TGS which divides down the TX frequency. So if TX freq used to clock the ICL 7660, then maybe would need further divider for making tone for audio -- so trade off is by using unsynchronized oscillator for negative supply and audio tone, you don't need a divider chip on board, but maybe some interfering EMI is generated.
-SB
Interesting that Silver Sabre plus seems to work at +5 volts, not +8 like TGS.
Also, wonder why they did not use TX signal as oscillator for ICL 7660 negative supply, to reduce chance of interference from another oscillator? Maybe because not rated well above 10kHz.
Perhaps related to other interesting feature which is that the ICL 7660 appears to generate the tone for the audio circuit, unlike the TGS which divides down the TX frequency. So if TX freq used to clock the ICL 7660, then maybe would need further divider for making tone for audio -- so trade off is by using unsynchronized oscillator for negative supply and audio tone, you don't need a divider chip on board, but maybe some interfering EMI is generated.
-SB
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