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-rw-r--r--src/librtlsdr.c18
1 files changed, 17 insertions, 1 deletions
diff --git a/src/librtlsdr.c b/src/librtlsdr.c
index f9aae37..529ab4f 100644
--- a/src/librtlsdr.c
+++ b/src/librtlsdr.c
@@ -955,6 +955,13 @@ int rtlsdr_set_direct_sampling(rtlsdr_dev_t *dev, int on)
/* disable spectrum inversion */
r |= rtlsdr_demod_write_reg(dev, 1, 0x15, 0x00, 1);
+ /* only enable In-phase ADC input */
+ r |= rtlsdr_demod_write_reg(dev, 0, 0x08, 0x4d, 1);
+
+ /* swap I and Q ADC, this allows to select between two inputs */
+ if (on > 1)
+ r |= rtlsdr_demod_write_reg(dev, 0, 0x06, 0x90, 1);
+
fprintf(stderr, "Enabled direct sampling mode\n");
dev->direct_sampling = 1;
} else {
@@ -970,10 +977,16 @@ int rtlsdr_set_direct_sampling(rtlsdr_dev_t *dev, int on)
/* enable spectrum inversion */
r |= rtlsdr_demod_write_reg(dev, 1, 0x15, 0x01, 1);
} else {
+ /* enable In-phase + Quadrature ADC input */
+ r |= rtlsdr_demod_write_reg(dev, 0, 0x08, 0xcd, 1);
+
/* Enable Zero-IF mode */
- rtlsdr_demod_write_reg(dev, 1, 0xb1, 0x1b, 1);
+ r |= rtlsdr_demod_write_reg(dev, 1, 0xb1, 0x1b, 1);
}
+ /* opt_adc_iq = 0, default ADC_I/ADC_Q datapath */
+ r |= rtlsdr_demod_write_reg(dev, 0, 0x06, 0x80, 1);
+
fprintf(stderr, "Disabled direct sampling mode\n");
dev->direct_sampling = 0;
}
@@ -1193,6 +1206,9 @@ int rtlsdr_open(rtlsdr_dev_t **out_dev, uint32_t index)
/* disable Zero-IF mode */
rtlsdr_demod_write_reg(dev, 1, 0xb1, 0x1a, 1);
+ /* only enable In-phase ADC input */
+ rtlsdr_demod_write_reg(dev, 0, 0x08, 0x4d, 1);
+
/* the R820T uses 3.57 MHz IF for the DVB-T 6 MHz mode, and
* 4.57 MHz for the 8 MHz mode */
rtlsdr_set_if_freq(dev, R820T_IF_FREQ);