Hi,
I am trying to implement a delay free integrator with transfer function = 1/(1-Z^-1) using the model writer of the cadence virtuoso the corresponding generated code is mentioned below.
Problem: When an input sampled signal of 1kHz and 900 microV ( = V_peak) is applied the output of the integrator is cosine but with output magnitude from 0 to 73 mV. Is there any problem with code or is there any special setting is required. If the input is 100 mV (= V_peak) then output of the integrator is in kVs.
Please help.
I am attaching screenshots of the schematic and transient response of the integrator (bottom is integrator output while top one is sample and hold output
)
// FUNCTION: Z-domain Filter
// VERSION: $Revision: 2.8 $
// AUTHOR: Cadence Design Systems, Inc.
//
// GENERATED BY: Cadence Modelwriter 2.31
// ON: Thu Feb 02 08:59:10 IST 2017
//
// Description: N degree Transfer functions of H(z)
// May be specified as a Polynomial or as Poles and Zeros.
//
// Complex Poles and Zeros must have conjugates.
//
//
// This model is an example, provided "as is" without express or
// implied warranty and with no claim as to its suitability for
// any purpose.
//
// PARAMETERS:
// first = Delay before taking first sample [S]
// samp = Sampling period [S]
// trans = Transtion time [S]
//
`include "discipline.h"
`include "constants.h"
// model ztrans
// Z-domain in Numerator-Denominator form
// Filter order is: 1 / 2
module ztrans (vin, vout);
input vin;
output vout;
electrical vin, vout;
parameter real samp = 3.90u from (0:inf);
// nxN is numerator of degree N.
// dxN is denominator of degree N.
parameter real nx0 = 1.0;
parameter real dx0 = 1.0;
parameter real dx1 = -1;
analog begin
V(vout) <+ zi_nd( V(vin), { nx0 },
{ dx0, dx1 }, samp);
end
endmodule