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Inf/Sup frequency shift scheme change to set bandwidth closer to device center frequency

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f4exb
2018-05-10 22:17:39 +02:00
parent 6a5a35285e
commit 4bb749ce65
11 changed files with 306 additions and 269 deletions
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plugins/samplesource/hackrfinput/readme.md
+16 -5
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@@ -75,11 +75,7 @@ This is the HackRF device ADC sample rate in S/s.
Use the wheels to adjust the sample rate. Left click on a digit sets the cursor position at this digit. Right click on a digit sets all digits on the right to zero. This effectively floors value at the digit position. Wheels are moved with the mousewheel while pointing at the wheel or by selecting the wheel with the left mouse click and using the keyboard arrows. Pressing shift simultaneously moves digit by 5 and pressing control moves it by 2.
<h3>7: Rx filter bandwidth</h3>
This is the Rx filter bandwidth in kHz. Possible values are: 1750, 2500, 3500, 5000, 5500, 6000, 7000, 8000, 9000, 10000, 12000, 14000, 15000, 20000, 24000, 28000 kHz.
<h3>8: Decimation factor</h3>
<h3>7: Decimation factor</h3>
The device stream from the HackRF is decimated to obtain the baseband stream. Possible values are:
@@ -90,6 +86,21 @@ The device stream from the HackRF is decimated to obtain the baseband stream. Po
- **16**: divide device stream sample rate by 16
- **32**: divide device stream sample rate by 32
<h3>8: Baseband center frequency position relative the the HackRF Rx center frequency</h3>
- **Cen**: the decimation operation takes place around the HackRF Rx center frequency Fs
- **Inf**: the decimation operation takes place around Fs - Fc.
- **Sup**: the decimation operation takes place around Fs + Fc.
With SR as the sample rate before decimation Fc is calculated as:
- if decimation n is 4 or lower: Fc = SR/2^(log2(n)-1). The device center frequency is on the side of the baseband. You need a RF filter bandwidth at least twice the baseband.
- if decimation n is 8 or higher: Fc = SR/n. The device center frequency is half the baseband away from the side of the baseband. You need a RF filter bandwidth at least 3 times the baseband.
<h3>9: Rx filter bandwidth</h3>
This is the Rx filter bandwidth in kHz. Possible values are: 1750, 2500, 3500, 5000, 5500, 6000, 7000, 8000, 9000, 10000, 12000, 14000, 15000, 20000, 24000, 28000 kHz.
<h3>10: Internal LNA gain</h3>
The LNA gain can be adjusted from 0 dB to 40 dB in 8 dB steps.