From 5d81a42564e1a69db86ff9a9eed88709d5768a64 Mon Sep 17 00:00:00 2001 From: f4exb Date: Sat, 1 Apr 2023 13:41:49 +0200 Subject: [PATCH] DATV demod: CNR adjustments --- plugins/channelrx/demoddatv/leansdr/sdr.h | 4 ++-- plugins/channelrx/demoddatv/readme.md | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/plugins/channelrx/demoddatv/leansdr/sdr.h b/plugins/channelrx/demoddatv/leansdr/sdr.h index deca6e933..8c042d941 100644 --- a/plugins/channelrx/demoddatv/leansdr/sdr.h +++ b/plugins/channelrx/demoddatv/leansdr/sdr.h @@ -1895,8 +1895,8 @@ struct cnr_fft : runnable { fprintf(stderr, "cnr_fft::cnr_fft: bw: %f FFT: %d\n", bandwidth, fft.size()); - if (bandwidth > 0.25) { - fail("cnr_fft::cnr_fft: CNR estimator requires Fsampling > 4x Fsignal"); + if (bandwidth != 0.5) { + fail("cnr_fft::cnr_fft: CNR estimator requires Fsampling = 2x Fsymbol"); } } diff --git a/plugins/channelrx/demoddatv/readme.md b/plugins/channelrx/demoddatv/readme.md index 5cfbb246a..960641bc9 100644 --- a/plugins/channelrx/demoddatv/readme.md +++ b/plugins/channelrx/demoddatv/readme.md @@ -48,7 +48,7 @@ This gauge gives the MER estimation. The averaged value appears on the right.

B.4: CNR estimation

-This gauge gives the CNR estimation. The averaged value appears on the right. Estimation is made comparing spectrum power in the center of the passband compared to the sides. The passband is the one presented to the demodulator and is always twice the symbol rate. the "center" is estimated at 60% of the full passband. Note that the RF filter comes before that and may change the aspect of the spectrum thus the best estimation is obtained when the RF filter width is close to twice the symbol rate and the surroundings are quiet. +This gauge gives the CNR estimation. The averaged value appears on the right. Estimation is made comparing spectrum power in the center of the passband compared to the sides. The passband is the one presented to the demodulator and is always twice the symbol rate. the "center" is estimated at 60% of the full passband. Note that the RF filter comes before that and may change the aspect of the spectrum thus the best estimation is obtained when the RF filter width is close to twice the symbol rate and the surroundings are quiet. This also means that you have to apply the correct symbol rate.

B.5: Output transport stream to UDP