Pspice to LTspice

[LuisMCP]

There is some parts in Pspice that are not found in LTspice.
LOPASS, HIPASS, BANDPASS are useful parts for simulation with filters.
GAIN, LAPLACE, SUM, DIFF, are useful for feedback systems and we can build complex filters (as RIAA eq.) quickly.
Most of these parts are found in ABM library of pspice.

Anybody get these parts for LTspice?

Regards,
Luis.

 

[Calvin]

Hi,

for RIAA sims I use a VCVS (component "e" in LTSpice) and the script laplace((75µ*s+1)*(3183µ*s+1))/((318µ*s+1)*(3.18µ*s+1))/{Gain} as the ´value´ parameter.
The 4 timeconstants stand for RIAA with Neumann-EQ, 2120Hz, 50Hz, 500Hz and finally 50kHz.
For standard RIAA delete 50kHzNeumann part *(3.18µ*s+1).
The RIAA1963 added a 7950µs/20Hz timeconstant at replay, not in the recording process.
Still though if You want this highpass added the laplace-term changes to laplace((75µ*s+1)*(3183µ*s+1)*(s/(7950µ*s+1)))/((318µ*s+1)*(3.18µ*s+1))/{Gain}

The parameter Gain defines the output voltage of component e.
The script reads for example: .param Gain=991
If fed with 1Vrms a gain-value of 991 gives -40dBV@1kHz, 10mVrms.
A Gain of 9916 gives -60dBV, 1mVrms.
Also I add a resistor and inductor in series with the VCVS with the values of the pickup´s R and L.

jauu
Calvin

 

[jcx]

you do have to be careful in using Laplace defs in .TRAN - the sw has to guess about sample times, convolution length in the discrete ifft
there are added hint parameters you can find in the doc to make them work better for your circuit's frequencies, sim length, time resolution

sims with R, L, C, and E, F, G, H dependent sources for filter functions can run faster, be more robust

 

[LuisMCP]

Thanks a lot, I didn't know that VCVS had Laplace function inside.
These dependant sources are certainly a powerful tool.

cheers.
luis.