To run return ratio (RR) for single-ended feedback ckts:

First, on an ECE Linux computer, copy (use the command 'cp') to a directory
of yours the files:  /home/hurst/212/rr_se/run_rr.sh , 
/home/hurst/212/rr_se/rrv_se.in , /home/hurst/212/rr_se/rri_se.in , 
and /home/hurst/212/rr_se/rr_se.sh .

Do 'chmod 0755 *.sh' to make the '.sh' shell scripts executable.

For a test run, also copy /home/hurst/212/rr_se/ckt_for_rr
and /home/hurst/212/rr_se/MOS_models_0.4um_approx .

As a test, run the command 'run_rr.sh' and you should get
plots of RR (mag and phase) versus frequency for the
circuit in ckt_for_rr (a 2-stage op amp). The 
low frequency RR of about 75 dB and RR = 0 dB at about
10^7 Hertz. 

To run a RR sim on your circuit:

1 - Find a break point that breaks all fb loops. Break the fb there.

2 - In your circuit file 'ckt_for_rr', name the nodes at the 
    the breaks as 'drive' and 'measure' 
    (either by modifying the netlist, or by using 0V voltage sources).
    The 'drive' node should be on the side of the break where
    you would connect an independent test source for 
    a return-ratio analysis. Don't include any independent sources
    in your file; they are included in the HSPICE files rri_se.in
    and rrv_se.in that will '.include' your 'ckt_for_rr' file.

3 - The HSPICE input files are called rri_se.in and rrv_se.in for
    single-ended (SE) return-ratio simulations. Your ckt netlist is assumed 
    to be named 'ckt_for_rr', which is called by these HSPICE input files. 

4 - The command for running the return-ratio simulation is: 

     run_rr.sh

     which runs the commands:

   	hspice rrv_se.in > rrv_se.out   (computes RR'v)
   	hspice rri_se.in > rri_se.out   (computes RR'i)
   	rr_se.sh      (combines RR'v and RR'i to give RR, plots result and
			writes result to a file called "rr_se.out.rr")

(Note: The rri_se.in and rrv_se.in files may be somewhat confusing,
as I'm using files for simulating common-mode return ratio in 
fully differential circuits here to simulate the RR of a single-ended
circuit. Prof. Lewis' RR simulation files on the ECE 112 web page
may be easier to understand. But either approach should give the same 
result.)