Fleetsync II decoder to use it. Adds instrumented version of the decoder
and a new Fleetsync2 FX pane to the DemodulatorViewerFX tool.
Note: the remaining AFSK-1200 based decoders will all be ported to use
this new AFSK1200 decoder (MDC1200, Tait1200, LowJack1200).
Deprecates the Listener<Boolean> interface method in the MessageFramer
to optimize for primitive booleans and reduce impact on memory. Will
remove this interface once the AFSK1200 decoders are updated.
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 ...
filter structure. Updated the channel results array buffer to produce
reusable buffers.
This has dropped the overall memory usage considerably when profiling.
Resolved issue in the processing chain where polyphase channel sources
were not being stopped and were stacking up in memory.
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.
samples prior to interpolation.
Resolves issue with using incorrect quadrature index when pulling a
sample from the interpolating buffer.
Resolves issue where the instrumented version of the interpolating
buffer was being constructed in the non-interpolated decoder component.
was not computationally feasible with my 3rd Gen i7 processor running
and airspy at 10 MHz. Restructured the polyphase channelizer to use
vector iteration structures that the JDK 9 JIT compiler can translate
into SIMD instructions. Separated the IFFT processing from the filter
process so that they can be executed on separate threads and this allows
the processing to occur real time.
P25 C4FM decoding at 25 kHz channel sample rate using an airspy
10MHz sample stream seems to be working nicely with ~25% CPU usage and
~300 to 500 MB memory usage. Incremental (parallel) channel decoding
should have a minimal increase in CPU loading since all of the 12.5 kHz
channels are available in the polyphase channelizer and the only
additional workload is the decoding of the 25 kHz sample stream.
There is still an issue with stopping channels and the channelizer keeps
processing, and occasionally when starting traffic channels something
deadlocks and causes out of memory.
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.
error calculator. After increasing the gain for symbol timing, this
new symbol evaluator class seems to track the signal very accurately
despite lots of noise and ISI.
timing error calculation with symbol decision. In the process of
changing over to this new class and remove the previous implementations
for the 3 values. This commit includes the partial implementation
so I can access from another dev machine.
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.
