... to support antenna/phantom power via a new device argument "bias"
(to match Airspy's existing bias power syntax). 0=disable and 1=enable.
I also added a device argument to control bias power at transmit time. I
named this option differently - "bias_tx" - to avoid accidentally
enabling bias power in transmit mode when an LNA may be attached in an
input amplifier configuration.
Original patch provided by Brad Hein
folowing rtl-sdr commit 89f73b183f2dac9c0dd75beca4cf2f77f20c4a36
So far we had 32 * 256KB which was a bit overkill, 15 are more than
enough.
15 was chosen instead of 16 because at least on Linux there seems to be
a system-wide limit of 63 transfers (when they are 256KB large), so 4
dongles can be used on a single machine without lowering the default
transfer number.
Unfortunately libhackrf still doesn't offer a way to enumerate devices
*or* to open a specific device by index or it's serial number. Thus we
have implemented a rather hack-ish way to detect the presence of a
device by trying to open it and closing right after that.
This allows a block to enable an associated driver to begin
transfering data just before we start to execute the scheduler.
The end result is that this reduces latency in the pipeline
when dealing with audio devices, usrps, etc.
the following named gain stages are available:
RF: MGA-81563, switchable 0 or 14dB
IF: MAX2837 LNA, 0 to 40dB in 8dB steps
BB: MAX2837 VGA, 0 to 62dB in 2dB steps
features:
- gain control for LNA & VGA
- frequency error correction
- automatic baseband filter
- up to 20M sampling rate
limitations:
- no DC offset correction implemented (yet)
- no RX preamplifier control (disabled by default)
- high sampling rates may not work on slow machines