diff options
| author | Kyle Keen <keenerd@gmail.com> | 2014-01-23 07:31:34 -0500 |
|---|---|---|
| committer | Steve Markgraf <steve@steve-m.de> | 2014-01-23 23:26:41 +0100 |
| commit | f459214894f1eb7d633a7f71165065b9974540b9 (patch) | |
| tree | 499d49de5c311a14e2aef460a9dc859dbbfcacfd | |
| parent | 835bd23542f1ec3f48e3da918cb6f80a6f9ea92a (diff) | |
rtl_power: fix dBm math
Signed-off-by: Steve Markgraf <steve@steve-m.de>
| -rw-r--r-- | src/rtl_power.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/src/rtl_power.c b/src/rtl_power.c index e96dd2a..f28055b 100644 --- a/src/rtl_power.c +++ b/src/rtl_power.c @@ -623,6 +623,12 @@ void downsample_iq(int16_t *data, int length) //remove_dc(data+1, length-1); } +long real_conj(int16_t real, int16_t imag) +/* real(n * conj(n)) */ +{ + return ((long)real*(long)real + (long)imag*(long)imag); +} + void scanner(void) { int i, j, j2, f, n_read, offset, bin_e, bin_len, buf_len, ds, ds_p; @@ -691,11 +697,11 @@ void scanner(void) fix_fft(fft_buf+offset, bin_e); if (!peak_hold) { for (j=0; j<bin_len; j++) { - ts->avg[j] += (long) abs(fft_buf[offset+j*2]); + ts->avg[j] += real_conj(fft_buf[offset+j*2], fft_buf[offset+j*2+1]); } } else { for (j=0; j<bin_len; j++) { - ts->avg[j] = MAX((long) abs(fft_buf[offset+j*2]), ts->avg[j]); + ts->avg[j] = MAX(real_conj(fft_buf[offset+j*2], fft_buf[offset+j*2+1]), ts->avg[j]); } } ts->samples += ds; |