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increase vga gain at lband for better SNR

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This commit is contained in:
Carl 2024-03-27 18:32:04 +08:00
parent 63ce7ca40e
commit e47685ebf0
2 changed files with 39 additions and 4 deletions
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1
include/tuner_r82xx.h
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@ -80,6 +80,7 @@ struct r82xx_priv {
enum r82xx_xtal_cap_value xtal_cap_sel; enum r82xx_xtal_cap_value xtal_cap_sel;
uint16_t pll; /* kHz */ uint16_t pll; /* kHz */
uint32_t int_freq; uint32_t int_freq;
uint32_t rf_freq;
uint8_t fil_cal_code; uint8_t fil_cal_code;
uint8_t input; uint8_t input;
int has_lock; int has_lock;

38
src/tuner_r82xx.c
View File

@ -222,7 +222,25 @@ static const struct r82xx_freq_range freq_ranges[] = {
/* .xtal_cap20p = */ 0x00, /* R16[1:0] 0pF (00) */ /* .xtal_cap20p = */ 0x00, /* R16[1:0] 0pF (00) */
/* .xtal_cap10p = */ 0x00, /* .xtal_cap10p = */ 0x00,
/* .xtal_cap0p = */ 0x00, /* .xtal_cap0p = */ 0x00,
}, {
/* .freq = */ 1000, /* Start freq, in MHz */
/* .open_d = */ 0x00, /* high */
/* .rf_mux_ploy = */ 0x40, /* R26[7:6]=1 (bypass) R26[1:0]=0 (highest) */
/* .tf_c = */ 0x00, /* R27[7:0] highest,highest */
/* .xtal_cap20p = */ 0x00, /* R16[1:0] 0pF (00) */
/* .xtal_cap10p = */ 0x00,
/* .xtal_cap0p = */ 0x00,
}, {
/* .freq = */ 1500, /* Start freq, in MHz */
/* .open_d = */ 0x00, /* high */
/* .rf_mux_ploy = */ 0x40, /* R26[7:6]=1 (bypass) R26[1:0]=0 (highest) */
/* .tf_c = */ 0x00, /* R27[7:0] highest,highest */
/* .xtal_cap20p = */ 0x00, /* R16[1:0] 0pF (00) */
/* .xtal_cap10p = */ 0x00,
/* .xtal_cap0p = */ 0x00,
} }
}; };
static int r82xx_xtal_capacitor[][2] = { static int r82xx_xtal_capacitor[][2] = {
@ -986,8 +1004,16 @@ int r82xx_set_gain(struct r82xx_priv *priv, int set_manual_gain, int gain)
if (rc < 0) if (rc < 0)
return rc; return rc;
/* set fixed VGA gain for now (16.3 dB) */ /* set fixed VGA gain based on frequency */
rc = r82xx_write_reg_mask(priv, 0x0c, 0x08, 0x9f); if (priv->rf_freq > MHZ(1500)) {
rc = r82xx_write_reg_mask(priv, 0x0c, 0x0f, 0x9f); // Max 40.5 dB
}
else if (priv->rf_freq > MHZ(1000)) {
rc = r82xx_write_reg_mask(priv, 0x0c, 0x0b, 0x9f);
}
else {
rc = r82xx_write_reg_mask(priv, 0x0c, 0x08, 0x9f); // 16.3 dB
}
if (rc < 0) if (rc < 0)
return rc; return rc;
@ -1023,8 +1049,15 @@ int r82xx_set_gain(struct r82xx_priv *priv, int set_manual_gain, int gain)
if (rc < 0) if (rc < 0)
return rc; return rc;
/* set fixed VGA gain based on frequency */
if (priv->rf_freq > MHZ(1500)) {
rc = r82xx_write_reg_mask(priv, 0x0c, 0x0f, 0x9f);
}
else {
/* set fixed VGA gain for now (26.5 dB) */ /* set fixed VGA gain for now (26.5 dB) */
rc = r82xx_write_reg_mask(priv, 0x0c, 0x0b, 0x9f); rc = r82xx_write_reg_mask(priv, 0x0c, 0x0b, 0x9f);
}
if (rc < 0) if (rc < 0)
return rc; return rc;
} }
@ -1145,6 +1178,7 @@ int r82xx_set_freq(struct r82xx_priv *priv, uint32_t freq)
/* if it's an RTL-SDR Blog V4, automatically upconvert by 28.8 MHz if we tune to HF /* if it's an RTL-SDR Blog V4, automatically upconvert by 28.8 MHz if we tune to HF
* so that we don't need to manually set any upconvert offset in the SDR software */ * so that we don't need to manually set any upconvert offset in the SDR software */
upconvert_freq = is_rtlsdr_blog_v4 ? ((freq < MHZ(28.8)) ? (freq + MHZ(28.8)) : freq) : freq; upconvert_freq = is_rtlsdr_blog_v4 ? ((freq < MHZ(28.8)) ? (freq + MHZ(28.8)) : freq) : freq;
priv->rf_freq = upconvert_freq;
lo_freq = upconvert_freq + priv->int_freq; lo_freq = upconvert_freq + priv->int_freq;