Lines Matching defs:N
93 static u32 int_goertzel(s16 x[], u32 N, u32 freq)
107 for (i = 0; i < N; i++) {
118 * XXX: N must be low enough so that N*N fits in s32.
121 divisor = N * N;
127 static u32 freq_magnitude(s16 x[], u32 N, u32 freq)
129 u32 sum = int_goertzel(x, N, freq);
134 static u32 noise_magnitude(s16 x[], u32 N, u32 freq_start, u32 freq_end)
141 if (N > 192) {
143 x += (N - 192);
144 N = 192;
150 sum += int_goertzel(x, N, freq_start);
157 static s32 detect_a2_a2m_eiaj(struct cx88_core *core, s16 x[], u32 N)
186 carrier = freq_magnitude(x, N, carrier_freq);
187 stereo = freq_magnitude(x, N, stereo_freq);
188 dual = freq_magnitude(x, N, dual_freq);
189 noise = noise_magnitude(x, N, FREQ_NOISE_START, FREQ_NOISE_END);
224 static s32 detect_btsc(struct cx88_core *core, s16 x[], u32 N)
226 s32 sap_ref = freq_magnitude(x, N, FREQ_BTSC_SAP_REF);
227 s32 sap = freq_magnitude(x, N, FREQ_BTSC_SAP);
228 s32 dual_ref = freq_magnitude(x, N, FREQ_BTSC_DUAL_REF);
229 s32 dual = freq_magnitude(x, N, FREQ_BTSC_DUAL);
237 static s16 *read_rds_samples(struct cx88_core *core, u32 *N)
259 *N = sample_count;
275 u32 N = 0;
288 samples = read_rds_samples(core, &N);
298 ret = detect_a2_a2m_eiaj(core, samples, N);
301 ret = detect_btsc(core, samples, N);