mirror of https://github.com/drowe67/librtlsdr.git
better usage of R820T filters - parts from Alexander Kurpiers (DL8AAU)
* center frequencies fixed for very narrow bandwidth selection, when IF center is moved to allow usage of IF filter corner. additional selection of sideband - with slightly different bandwidth value Signed-off-by: hayati ayguen <h_ayguen@web.de>development
hayati ayguen
parent
00fe84cac1
commit
ec5ebcc851
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@ -1167,6 +1167,26 @@ static const int r82xx_if_low_pass_bw_table[] = {
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1700000, 1600000, 1550000, 1450000, 1200000, 900000, 700000, 550000, 450000, 350000
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};
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#if 0
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static const int r82xx_bw_tablen = 17;
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/* Hayati: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 */
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/* shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted centered centered centered centered ?! */
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static const int r82xx_bws[]= { 200000, 300000, 400000, 500000, 600000, 700000, 800000, 900000, 1000000, 1100000, 1200000, 1300000, 1400000, 1550000, 1700000, 1900000, 2200000 };
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static const uint8_t r82xx_0xb[]= { 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xCF, 0xAF, 0x8F, 0x51 };
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static const int r82xx_if[] = { 1900000, 1850000, 1800000, 1750000, 1700000, 1650000, 1600000, 1550000, 1500000, 1450000, 1400000, 1350000, 1300000, 1400000, 1450000, 1600000, 4700000};
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#else
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static const int r82xx_bw_tablen = 24;
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/* duplicated lower bandwidths to allow "sideband" selection: which is filtered with help of IF corner */
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/* Hayati: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 */
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/* shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted shifted centered centered centered centered ?! */
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static const int r82xx_bws[]= { 200000, 200400, 300000, 300400, 400000, 400400, 500000, 500400, 600000, 600400, 700000, 700400, 800000, 800400, 900000, 1000000, 1100000, 1200000, 1300000, 1400000, 1550000, 1700000, 1900000, 2200000 };
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static const uint8_t r82xx_0xb[]= { 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xEF, 0xCF, 0xAF, 0x8F, 0x51 };
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static const int r82xx_if[] = { 1900000, 700000, 1850000, 750000, 1800000, 800000, 1750000, 850000, 1700000, 900000, 1650000, 950000, 1600000, 1000000, 1550000, 1500000, 1450000, 1400000, 1350000, 1300000, 1400000, 1450000, 1600000, 4700000};
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#endif
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#define FILT_HP_BW1 350000
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#define FILT_HP_BW2 380000
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int r82xx_set_bandwidth(struct r82xx_priv *priv, int bw, uint32_t rate, uint32_t * applied_bw, int apply)
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@ -1195,7 +1215,7 @@ int r82xx_set_bandwidth(struct r82xx_priv *priv, int bw, uint32_t rate, uint32_t
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reg_0b = 0x2a;
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if (apply)
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priv->int_freq = 4570000;
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} else if (bw > r82xx_if_low_pass_bw_table[0] + FILT_HP_BW1 + FILT_HP_BW2) {
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} else if (bw > 4500000) {
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// BW: 6 MHz
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*applied_bw = 6000000;
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reg_0a = 0x10;
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@ -1203,49 +1223,37 @@ int r82xx_set_bandwidth(struct r82xx_priv *priv, int bw, uint32_t rate, uint32_t
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if (apply)
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priv->int_freq = 3570000;
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} else {
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reg_0a = 0x00;
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reg_0b = 0x80;
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if (apply)
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priv->int_freq = 2300000;
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if (bw > r82xx_if_low_pass_bw_table[0] + FILT_HP_BW1) {
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bw -= FILT_HP_BW2;
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if (apply)
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priv->int_freq += FILT_HP_BW2;
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real_bw += FILT_HP_BW2;
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} else {
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reg_0b |= 0x20;
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}
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if (bw > r82xx_if_low_pass_bw_table[0]) {
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bw -= FILT_HP_BW1;
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if (apply)
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priv->int_freq += FILT_HP_BW1;
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real_bw += FILT_HP_BW1;
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} else {
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reg_0b |= 0x40;
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}
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// find low-pass filter
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for(i = 0; i < ARRAY_SIZE(r82xx_if_low_pass_bw_table); ++i) {
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if (bw > r82xx_if_low_pass_bw_table[i])
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for(i=0; i < r82xx_bw_tablen-1; ++i) {
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/* bandwidth is compared to median of the current and next available bandwidth in the table */
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if (bw < (r82xx_bws[i+1] + r82xx_bws[i])/2)
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break;
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}
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--i;
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reg_0b |= 15 - i;
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real_bw += r82xx_if_low_pass_bw_table[i];
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reg_0a = 0x0F;
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reg_0b = r82xx_0xb[i];
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real_bw = ( r82xx_bws[i] / 1000 ) * 1000; /* round on kHz */
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#if 0
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fprintf(stderr, "%s: selected idx %d: R10 = %02X, R11 = %02X, Bw %d, IF %d\n"
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, __FUNCTION__, i
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, (unsigned)reg_0a
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, (unsigned)reg_0b
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, real_bw
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, r82xx_if[i]
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);
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#endif
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*applied_bw = real_bw;
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if (apply)
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priv->int_freq -= real_bw / 2;
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priv->int_freq = r82xx_if[i];
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}
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#if USE_R82XX_ENV_VARS
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// hacking RTLSDR IF-Center frequency - on environment variable
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if ( priv->filterCenter && apply )
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{
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#if 0
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fprintf(stderr, "*** applied IF center %d\n", priv->filterCenter);
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#endif
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priv->int_freq = priv->filterCenter;
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}
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#endif
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@ -1268,7 +1276,7 @@ int r82xx_set_bandwidth(struct r82xx_priv *priv, int bw, uint32_t rate, uint32_t
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#endif
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/* Register 0xA = R10 */
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reg_mask = 0x10; // default: 0001 0000
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reg_mask = 0x0F; // default: 0001 0000
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#if USE_R82XX_ENV_VARS
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if ( priv->haveR10H ) {
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reg_0a = ( reg_0a & ~0xf0 ) | ( priv->valR10H << 4 );
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@ -1279,7 +1287,6 @@ int r82xx_set_bandwidth(struct r82xx_priv *priv, int bw, uint32_t rate, uint32_t
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reg_mask |= 0x0f;
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}
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#endif
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rc = r82xx_write_reg_mask_ext(priv, 0x0a, reg_0a, reg_mask, __FUNCTION__);
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if (rc < 0) {
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fprintf(stderr, "ERROR setting I2C register 0x0A to value %02X with mask %02X\n", (unsigned)reg_0a, (unsigned)reg_mask);
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