diff options
| author | Sylvain Munaut <tnt@246tNt.com> | 2011-10-19 08:31:18 +0200 |
|---|---|---|
| committer | Sylvain Munaut <tnt@246tNt.com> | 2011-10-19 08:31:18 +0200 |
| commit | 63e9d84adbc59047cb9bb27f0d89fab330e8b7f2 (patch) | |
| tree | 345d6f982a58f1606a3be523ee80bf469c30270b /src/sdr | |
| parent | 93848d25af9f20e4ac75ea00bf65490d2b56cc05 (diff) | |
sdr/fcch: Add equation for the up/down/dual chirps doc
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Diffstat (limited to 'src/sdr')
| -rw-r--r-- | src/sdr/fcch.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/src/sdr/fcch.c b/src/sdr/fcch.c index ec8a9fa..50dfc1e 100644 --- a/src/sdr/fcch.c +++ b/src/sdr/fcch.c @@ -49,7 +49,13 @@ * \param[in] up_down Selects chirp direction (0=down 1=up) * \returns A newly allocated complex vector containing the chirp * - * The length will be 117 * sps + * Up-Chirp: \f$\frac{\sqrt{2}}{2}\cdot e^{j\left( + * 0.64\pi\left(t-\frac{T}{2}\right)^2/T^2\right)}\f$ + * + * Down-Chirp: \f$\frac{\sqrt{2}}{2}\cdot e^{-j\left( + * 0.64\pi\left(t-\frac{T}{2}\right)^2/T^2\right)}\f$ + * + * The length will be 117 * sps */ static struct osmo_cxvec * gmr1_sdr_fcch_gen_up_down_chirp(int sps, int up_down) @@ -85,7 +91,10 @@ gmr1_sdr_fcch_gen_up_down_chirp(int sps, int up_down) * \param[in] sps Oversampling rate * \returns A newly allocated complex vector containing the chirp * - * The length will be 117 * sps + * \f$\frac{\sqrt{2}}{2}\cdot e^{j\left( + * 0.64\pi\left(t-\frac{T}{2}\right)^2/T^2\right)}\f$ + * + * The length will be 117 * sps */ static struct osmo_cxvec * gmr1_sdr_fcch_gen_up_chirp(int sps) @@ -97,7 +106,10 @@ gmr1_sdr_fcch_gen_up_chirp(int sps) * \param[in] sps Oversampling rate * \returns A newly allocated complex vector containing the chirp * - * The length will be 117 * sps + * \f$\frac{\sqrt{2}}{2}\cdot e^{-j\left( + * 0.64\pi\left(t-\frac{T}{2}\right)^2/T^2\right)}\f$ + * + * The length will be 117 * sps */ static struct osmo_cxvec * gmr1_sdr_fcch_gen_down_chirp(int sps) @@ -109,7 +121,9 @@ gmr1_sdr_fcch_gen_down_chirp(int sps) * \param[in] sps Oversampling rate * \returns A newly allocated complex vector containing the dual chirp * - * The length will be 117 * sps. The vector is also 'real only'. + * \f$\sqrt{2}\cdot\cos\left(0.64\pi\left(t-\frac{T}{2}\right)^2/\;T^2\right)\f$ + * + * The length will be 117 * sps. The vector is also 'real only'. */ static struct osmo_cxvec * gmr1_sdr_fcch_gen_dual_chirp(int sps) |