only update the center frequency when needed and to place the set of
decoding channels adjacent to the right side of the tuner's center
frequency when the complete set of channels fit into the usable half
bandwidth of the tuner.
Adds 500 ms delay to initial registering for samples from all tuners to
feed the spectral display/waterfall. The existing approach of immediately
registering for samples was causing the airspy tuner to lockup
aperiodically. Investigation via debugger didn't show any application
thread locks ... usb master processor was continuing to service libusb
timeouts. Unable to debug internal airspy processes. Adding the delay
to startup seems to be a usable solution.
Updates decoder types to specify channel sample rate and pass/stop
frequencies for requested channels. Updates tuner channel source
managers to accept a channel specification for channels that are
allocated.
channel manager so that channel source requests can have a start
timestamp specified and the channel can be preloaded with samples from
the delay buffer. If no timestamp is specified, current time is assumed.
This feature requires corresponding updates to any decoder that wishes
to implement the timestamped sample preloading functionality.
buffers. None of the decoders currently support this yet, but the P25
will be updated to provide bitstream output for recording.
Renames the ReusableBuffer class to ReusableFloatBuffer for
consistency.
and auto-correction for R820T tuners.
-Updated TunerModel and TunerViewPanel to add 2 new columns to
display the current tuner's PPM setting and (when available) the
measured frequency error averaged over 5 second intervals provided by
certain decoders (e.g. P25 C4FM and LSM). Frequency error value from
P25 decoders is provided from the Costas Loop PLL once 2 or more P25
message sync events have been observed in a short period.
-Updated R820T tuner to auto-correct PPM when measured frequency error
exceeds the +/- 0.4PPM threshold for a period of 30 seconds or more.
Feature can be enabled/disabled by user in the tuner editor panel.
Resolved several issues with P25 C4FM/LSM decoders that was impacting
performance related to channel misalignment from tuner PPM offsets.
Resolves an issue with the previous implementation where the tuner
editor was being refreshed repeatedly to update the lock state for the
tuner, rendering the editor almost completely unusable.
Now updates only the frequency control and the sample rate control to
reflect the tuner's lock state.
Adds capability to disable spectral display.
Adds right-click context
menu items to disable display and/or reenable display by selecting
another tuner.
Adds view menu items to disable spectral display or show a tuner.
Persists spectral display enabled state across application run sessions.
The C4FM and LSM decoders were issuing a PLL reset with each new
channel that was allocated, causing any existing decoding channels to
be disrupted. Decoding re-sync delays or inability to recapture the
signal for decoding would likely result as the tuner's overall PPM
caused misadjustment in the channel.
Resolved a NPE that was occurring in the FrequencyController for
sample rate changes.
sample rates.
Resolves issue in PolyphaseChannelManager responding to sample rate
changes in the tuner. The manager now recreates the channelizer when
needed if the tuner's sample rate has changed since the last time the
channelizer was used.
Updates the Tuner selection view to reflect tuner lock state. Updates
the tuner editors to enable/disable frequency controller and sample
rate controls according to the tuner's lock state.
Refactors a MixerReader instance from the RealMixerSource so that it
can be reused for both real and complex data outputs.
Updates RealMixerSource to use refactored MixerReader and use a default
sample rate of 8 kHz.
Updates the ComplexMixer to use the refactored MixerReader.
Updates the FCD 1/2 tuners for compatibility with the new ComplexMixer.
Removes several unused classes.
channelizer sub-system is functionally complete.
Updated the channelizer and synthesizer filter design methods to use a
Kaiser windowed Nyquist filter. Updated the synthesizer filter design
to use a new cutoff frequency of 105% of the channel bandwidth to
resolve a slight dip in the synthesized channel gain at the channel
union region.
Updated the 2 channel output processor to use a low-pass filter that
is designed for the runtime channel sample rate versus hard-coded 12.5
khz.
Testing and redesign continues ...
that is currently up/down converting the signal of interest, but the
synthesizer is not correctly combining the original two channels.
Some experimentation with the tap count for the channelizer indicates
that we can cut the tap count in half and still have decent decoding
on the P25 decoder when paired to an aligned channelized output. The
2-channel synthesized output decodes partially, but needs more work.
Resolved issue with channel gain in the channelizer that was making the
sample values so small that they were registering as zero when converted
from float to 16-bit int value in the complex wave recorder.
adds Feed forward gain support to the C4FM DQPSK demodulator which seems
to improve output from the interpolating sample buffer at each symbol
period. Updates the symbol timing gain for C4FM to decrease the gain a
bit since the feed forward gain is providing a better interpolated symbol.
updates the LSM decoder to follow the same design pattern. Adds LSM
decoder support to the demodulator viewer application. The current
symbol timing gain for LSM is set too high -- is using the C4FM gain
and causes too much fluctuation in the timing error.
based on the P25 LSM decoder using a costas loop and a gardner detector.
Updates the Demodulator Viewer FX application to add in a symbol chart
and a phase error chart. The decoder won't lock on yet ... still a wip.
so that on startup, the application attempts to source the channel from
the preferred tuner.
If the tuner is currently not available, or if the tuner cannot source
the channel, then the next available tuner is selected.
when the tuner controller indicates that there is a center DC spike
blocked region or when the tuner has clipped outer spectral regions
resulting in less than 100% usable bandwidth.
produces a significant reduction in memory usage, especially for tuners
like the airspy and hackrf that produce 10/20 MSPS sample rates. This
is observed to be around 66% reduction in peak memory usage and provides
a more stable memory utilization across time reducing stress on the
garbage collector.
Use of these reusable memory buffers will be pushed further down into
the processing chain modules to ensure we keep new object creation
to the lowest levels possible.
