In Reply to: Re: Adding a DC bias to a differential clock signal posted by David Ashby on 04/15/02 at 7:19 AM:
For reference, the signal is RS485 manchester encoded @ 10Mhz. I have a couple of additional questions:
1. Are you saying (in the first paragraph), that a correct signal transformer (attached in line with the manchester encoded signal) will be sufficient to establish the wanted DC bias without having to insert a separate voltage (with proper frequency) source?
2. Or are you eluding to the fact that a signal transformer (with proper frequency) and correct voltage divider can be used with the existing 120VAC to 7.8VDC (yes, low frequency) power transformer and then coupled with the existing signal line?
3. In either case, would I be concerned with proper impedance matching? The Load (receiver) has an impedance of ~130 ohms, and the manchester encoded signal source also has an impedance of 130 ohms.
Thanks for your help.