...If the logic low output doesn't go all the way to GND, or goes slightly negative, adjust the 2.2K resistor slightly.
Recommend using 1% tolerance resistors, if available.
Before you connect a CD4050, try to see if there is a negative dc level in your output. My data sheet says not to go below 0.5V input. As Paul mentioned its possible to shift the dc point via resistor changes. Hence recommending tighter resistor values.
That's one reason I suggested an ac coupled circuit. But as Paul noted the modulated signal (data) can shift the dc average depending how low the effective data frequencies go. Changing the coupling capacitor may improve for some given ranges of data frequencies. In your case, my circuit could work for the data range you get from your keyboard. I guess you didn't try it? I don't know what a typical data signal you actually get, so its hard to know what won't work.
PeterB
For one more quick test, I replaced the resistors with 1K and 330 ohms. Indeed it's able to handle the speed much better with lower impedance.
View attachment 16691
But of course this loads the -10V signal with ~1K, meaning it has to drive 10 mA. Apparently my Siglent function generator can do that pretty well.
I'd be interest to see a 'scope shot of a data stream including your sync. Apparently LTSpice has a way of using a data file to stimulate the circuit so one can see what the output would be with such a signal. Could you get me some samples of data?I emulated the circuit in everycircuit app, understand now what it is doing.
I'd be interest to see a 'scope shot of a data stream including your sync. Apparently LTSpice has a way of using a data file to stimulate the circuit so one can see what the output would be with such a signal. Could you get me some samples of data?
PeterB
I'd be interest to see a 'scope shot of a data stream including your sync. Apparently LTSpice has a way of using a data file to stimulate the circuit so one can see what the output would be with such a signal. Could you get me some samples of data?
PeterB