probe_dc :
A DC analysis probe for measuring DC transfer function.
The probe_dc
primitive measures the DC transfer function of a circuit by supplying a DC stimulus (stim
) and measuring the circuit’s response (resp
). That is, one can measure a DC transfer function by configuring a testbench that feeds the stim
output of this primitive to the circuit’s input and connects the circuit’s output to the resp
input of this primitive.
The probe_dc
primitive produces a DC signal for its stim
output, stepping from start
to stop
at an increment of step
. The change in stim
can be triggered either internally or externally depending on the value of the parameter period
. When period
is greater than 0, the change is triggered internally at a period of period
after an initial delay of delay
. When period
is 0, the change is triggered externally whenever the trig
input changes to a different value. Before making each change to stim
, the probe_dc
primitive takes a measurement on the resp
input and records the results in a table format to a text file named by the parameter filename
. For desired results, the triggering period must be set long enough for the circuit to reach its final DC response. Also, the simulation must be run longer than delay+period*(stop-start+step)/step
in order for the primitive to collect the entire transfer function.
Input/Output Terminals
Name | I/O | Type | Description |
stim | output | xreal | stimulus (to circuit) |
resp | input | xreal | response (from circuit) |
trig | input | xbit | trigger input |
Parameters
Name | Type | Default | Unit | Description |
filename | string | “probe_dc.dat” | None | output filename |
start | real | 0.0 | None | start value |
stop | real | 1.0 | None | stop value |
step | real | 0.1 | None | step value |
period | real | 0.0 | seconds | trigger period |
delay | real | 0.0 | seconds | initial delay |