What is the abbreviation for the 'RS' 'RD' RP'?

RS ; Series resistor?
RD ; ???
RP ; Parallel resistor?

Thanks.

 

RS : Resistance of Source
RD : Not represented in your picture
RP : Resistance of Pull-up

 

RS : Resistance of Source
RD : Not represented in your picture
RP : Resistance of Pull-up

There are formula, RS = Z0-RD

 

The figure shows the methods of harmonizing the logic gates with a long line.
Without harmonization of impedances can be used if the line is short.
If the line is long, it is necessary to produce an agreement.
Rd is the output impedance digital microchips (usually Rd < Z0).
Receive RD + RS = Z0-> RS = Z0-Rd. If Rd > Z0, so you cannot reconcile.
Usually Rin > > Z0. Rin-impedance digital chip.
Including on the output line resistor RP = Z0 you agree to the long line.
And Yes. Z0-characteristic impedance long line.

 

I found a circuit that shows RS .2 with a resistor symbol. the says RS=1+(R1+R2). Does this mean i need to have a standard resistor in that specific location of .2 ohms?

 

I found a circuit that shows RS .2 with a resistor symbol. the says RS=1+(R1+R2). Does this mean i need to have a standard resistor in that specific location of .2 ohms?

It would help a lot if you could post the schematic you are working with.

 

I see the posted document leads to this.
https://forums.xilinx.com/t5/Other-FPGA-Architectures/CML-to-LVDS-interface/td-p/763971
Max.