luke
/
ngspice
mirror of https://git.code.sf.net/p/ngspice/ngspice
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Special Nyquist scaling only for even length. 

Let nyquist bin not empty for odd vector
This commit is contained in:
dwarning 2026-03-20 13:33:39 +01:00 committed by Holger Vogt
parent 278841972c
commit b3a78b02cc
2 changed files with 15 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
src/frontend/com_fft.c
View File

@ -185,7 +185,10 @@ com_fft(wordlist *wl)
fdvec[i][j].cx_real = out[j][0]/scale;
fdvec[i][j].cx_imag = out[j][1]/scale;
}
if (length % 2 == 0) {
fdvec[i][fpts-1].cx_real = out[fpts-1][0]/scale/2.0;
fdvec[i][fpts-1].cx_imag = 0.0;
}
}
fftw_destroy_plan(plan_forward);
@ -220,7 +223,7 @@ com_fft(wordlist *wl)
fdvec[i][j].cx_real = in[2*j]/scale;
fdvec[i][j].cx_imag = in[2*j+1]/scale;
}
fdvec[i][fpts-1].cx_real = in[1]/scale;
fdvec[i][fpts-1].cx_real = in[1]/scale/2.0;
fdvec[i][fpts-1].cx_imag = 0.0;
tfree(in);
@ -416,15 +419,17 @@ com_psd(wordlist *wl)
fdvec[i][0].cx_real = out[0][0]*out[0][0]/intres;
fdvec[i][0].cx_imag = 0;
noipower = fdvec[i][0].cx_real;
for (j = 1; j < fpts-1; j++) {
for (j = 1; j < fpts; j++) {
fdvec[i][j].cx_real = 2.* (out[j][0]*out[j][0] + out[j][1]*out[j][1])/intres;
fdvec[i][j].cx_imag = 0;
noipower += fdvec[i][j].cx_real;
if (!finite(noipower))
break;
}
fdvec[i][fpts-1].cx_real = out[fpts-1][0]*out[fpts-1][0]/intres;
fdvec[i][fpts-1].cx_imag = 0;
if (length % 2 == 0) {
fdvec[i][fpts-1].cx_real = out[fpts-1][0]*out[fpts-1][0]/intres;
fdvec[i][fpts-1].cx_imag = 0;
}
noipower += fdvec[i][fpts-1].cx_real;
#else /* Green's FFT */

7
src/maths/cmaths/cmath4.c
View File

@ -781,7 +781,10 @@ cx_fft(void *data, short int type, int length, int *newlength, short int *newtyp
outdata[i].cx_real = out[i][0]/scale;
outdata[i].cx_imag = out[i][1]/scale;
}
if (length % 2 == 0) {
outdata[fpts-1].cx_real = out[fpts-1][0]/scale/2.0;
outdata[fpts-1].cx_imag = 0.0;
}
fftw_free(ind);
#else /* Green's FFT */
@ -808,7 +811,7 @@ cx_fft(void *data, short int type, int length, int *newlength, short int *newtyp
outdata[i].cx_real = datax[2*i]/scale;
outdata[i].cx_imag = datax[2*i+1]/scale;
}
outdata[fpts-1].cx_real = datax[1]/scale;
outdata[fpts-1].cx_real = datax[1]/scale/2.0;
outdata[fpts-1].cx_imag = 0.0;
#endif