diff --git a/src/fft/tests/spgram_autotest.c b/src/fft/tests/spgram_autotest.c
index ff06a198c..749b6e3a1 100644
--- a/src/fft/tests/spgram_autotest.c
+++ b/src/fft/tests/spgram_autotest.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007 - 2022 Joseph Gaeddert
+ * Copyright (c) 2007 - 2023 Joseph Gaeddert
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -35,8 +35,10 @@ void testbench_spgramcf_noise(unsigned int _nfft,
     unsigned int num_samples = 2000*_nfft;  // number of samples to generate
     float        nstd        = powf(10.0f,_noise_floor/20.0f); // noise std. dev.
     float        tol         = 0.5f; // error tolerance [dB]
-    if (liquid_autotest_verbose)
-        printf("  spgramcf test  (noise): nfft=%6u, wtype=%24s, noise floor=%6.1f\n", _nfft, liquid_window_str[_wtype][1], _noise_floor);
+    if (liquid_autotest_verbose) {
+        printf("  spgramcf test  (noise): nfft=%6u, wtype=%24s, noise floor=%6.1f\n",
+                _nfft, liquid_window_str[_wtype][1], _noise_floor);
+    }
 
     // create spectral periodogram
     spgramcf q = NULL;
@@ -92,8 +94,10 @@ void testbench_spgramcf_signal(unsigned int _nfft, int _wtype, float _fc, float
     float bw = 0.25f; // signal bandwidth (relative)
     unsigned int m = 25;
     float beta = 0.2f, n0 = -80.0f, tol = 0.5f;
-    if (liquid_autotest_verbose)
-        printf("  spgramcf test (signal): nfft=%6u, wtype=%24s, fc=%6.2f Fs, snr=%6.1f dB\n", _nfft, liquid_window_str[_wtype][1], _fc, _SNRdB);
+    if (liquid_autotest_verbose) {
+        printf("  spgramcf test (signal): nfft=%6u, wtype=%24s, fc=%6.2f Fs, snr=%6.1f dB\n",
+                _nfft, liquid_window_str[_wtype][1], _fc, _SNRdB);
+    }
 
     // create objects
     spgramcf     q     = spgramcf_create(_nfft, _wtype, _nfft/2, _nfft/4);
@@ -131,8 +135,13 @@ void testbench_spgramcf_signal(unsigned int _nfft, int _wtype, float _fc, float
         {.fmin=_fc-0.4f*bw, .fmax=_fc+0.4f*bw, .pmin=sn-tol, .pmax=sn+tol, .test_lo=1, .test_hi=1},
         {.fmin=_fc+0.6f*bw, .fmax=+0.5f,       .pmin=n0-tol, .pmax=n0+tol, .test_lo=1, .test_hi=1},
     };
+    char filename[256];
+    sprintf(filename,"autotest/logs/spgramcf_signal_%s_n%u_f%c%.0f_s%c%.0f.m",
+        liquid_window_str[_wtype][0], _nfft,
+        _fc < 0 ? 'm' : 'p', fabsf(_fc*1000),
+        _SNRdB < 0 ? 'm' : 'p', fabsf(_SNRdB*1000));
     liquid_autotest_validate_spectrum(psd, _nfft, regions, 3,
-        liquid_autotest_verbose ? "autotest/logs/spgramcf_signal.m" : NULL);
+        liquid_autotest_verbose ? filename : NULL);
 
     // destroy objects
     spgramcf_destroy(q);