Changes from SDRangelove

New features, enhancements and fixes

• Added ppm correction for the LO of RTL-SDR. This uses the corresponding function in the librtlsdr interface (range -99..99 ppm)
• Added a preset update button (the diskette with the yellow corner) to be able to save the current settings on an existing preset
• Added variable decimation in log2 increments from 2^0=1 to 2^4=16 allowing to see the full 2048 kHz of spectrum if so you wish
• Better handling of rtlsdr GUI display when settings change (initial load, load of presets)
• Added display and precise control of the shift frequency from center frequency of the NFM receivers.
• Removed useless spectrum visualizer in NFM receivers. Created a null sink class to fit corresponding parameter in NFMDemod class constructor.
• Added display and precise control of the shift frequency from center frequency of the SSB receivers.
• SSB filter bounds are tunable so that filter can be set off from center frequency allowing aural decoding of CW
• Make the sidebands appear correctly on SSB channel overlay. Limit to +/- 6 kHz to fit channel spectrum analyzer window
• SSB bandwidth can now be tuned in steps of 100 Hz
• NFM and SSB receiver in focus trigger the display of the central frequency line on the spectrum frequency scale thus facilitating its identification
• Added AM demod so now you can listen to air traffic!
• Added the possibility to change the brightness and/or color of the grid.
• Make the low cutoff frequency of the SSB filter variable so it can be used for CW also.
• NFM demodulation without using atan and smooth squelch with AGC suppressing most clicks on low level signals and hiss on carrier tails. Only useful modulation comes through.
• Added working WFM demodulation. Optimized for no atan2.
• OsmoSDR and GNURadio plugins removed from the build as they have too many bugs that are too difficult to correct
• New plugin for BladeRF interfacing libbladeRF directly
• Corrected the nasty audio band resampling bug preventing use of sample rates that are not power of 2 multiples of 48kHz. This was because the resampling ratio was calculated with an integer division instead of a float division.
• As a consequence of the above added more interesting values for the available sampling rates of the BladeRF plugin
• Variable span for the SSB demod down to 1.5 kHz
• Filter out CTCSS tones for audio and full CTCSS support in NFMDemod
• Enhancement of the NFM squelch mimicking professional analog squelch circuits (based on balance between two AF filters)
• Added a channel analyzer plugin focusing on measurement (DSA/DSO functionnality). Basic functions.
• Added a scope widget in the channel analyzer plugin
• Channel analyzer bandwidth up to half the available RF (IF) bandwidth (was 48k fixed)
• Enhanced scope display and controls: scale display, better X (time) and Y scales control, grid fit to scale, effectively implementing triggers, trigger on magnitude and phase, properly handling time shift, ...
• Enhanced spectrum display: Histogram: wider decay range, make stroke and late holdoff adjustable. Added option to show live spectrum (had only max hold before).
• Enhanced channel analyzer: enhanced scope and spectrum displays as mentioned above, make the spectrum display synchronous to scope (hence triggerable a la E4406A).
• Sort channel plugins by delta frequency and type before saving to preset
• Implemented scope pre-trigger delay
• Implemented variable scope memory depth
• Implemented trigger delay
• Trigger on both edges
• Spectrum histogram clear
• Trigger line display for all trigger modes
• Coarse and fine trigger level sliders
• Minimalist recording (no file choice)
• File sample source plugin (recording reader)
• Scope: trace history
• Scope: trigger countdown
• Scope: multiple trigger chaining
• Scope: new mode with linear IQ (two traces) on the primary display and polar IQ on the secondary display
• New UDP source plugin to connect to an external demodulator (ex: GNU radio) via UDP ports
• Binaural option for SSB demod
• DSB option for SSB
• Mute option for NFM channel
• New Broadcast FM demodulator with stereo support
• RDS support in Broadcast FM demodulator

Major redesign

• Make the DSP engine global static simplifying access to it. Have a distinct object to handle the thread
• Fixed startup initialization sequence. New initialization phase in DSP engine and new ready state
• Synchronous messaging class to push message to thread and wait for completion relieving the message queuing mechanism from this role
• Message queuing and handling redesign. Still not completely satisfactory
• Objects have their own input and output message queues
• Dedicated message queue to communicate to the GUI for objects coupled with a GUI
• Optimizations with Valgrind cachegrind
• Corrected decimators bit shifting so that the number of effective output bits is constant and fill the internal sample width
• Separate library to support all flavours of FunCube dongles. Rewritten FCD plugins.
• Allow several sample source plugins to share the same presets for what is common
• Prepare grounds for future Tx operations with Tx spectrum display in the main window
• Merged include-gpl into include and removed GPL dribble in About dialog
• Many other little things...

Recent fixes

• Fixed typo in cmake file
• Added .desktop file
• Fixed RTL-SDR sample rate slider range