I found this circuit on the internet and I suspect it has a problem. It is a receiver for time code transmissions. In the UK these are broadcast on 60kHz with a 100ms, 200ms, or 300ms break every second.
D1 and C9 are the envelope detector for this receiver, but I see no discharge path C9. I guess it needs a discharge resistor across C9. Given the 60kHz carrier frequency and 100ms minimum gap what time constant should I use here?
I don't propose to breadboard this as I expect it would end up as an oscillator rather than a receiver so it will be going straight to PCB so a 'get it right first time' approach is desired.
Are there any other visible problems?
D1 and C9 are the envelope detector for this receiver, but I see no discharge path C9. I guess it needs a discharge resistor across C9. Given the 60kHz carrier frequency and 100ms minimum gap what time constant should I use here?
I don't propose to breadboard this as I expect it would end up as an oscillator rather than a receiver so it will be going straight to PCB so a 'get it right first time' approach is desired.
Are there any other visible problems?