Documentation on AM, NFM and SSB demodulator plugins

Readme.md

@@ -95,7 +95,7 @@ If you use your own location for librtlsdr install directory you need to specify
 
 Linux only.
 
-SDRplay devices are supported through the [libmirisdr-4](https://github.com/f4exb/libmirisdr-4) library found in this very same Github space. There is no package distribution for this library and you will have to clone it, build and install it in your system. However Windows and Debian packages of SDRangel contain a pre-compiled version of this library.
+SDRplay devices are supported through the [libmirisdr-4](https://github.com/f4exb/libmirisdr-4) library found in this very same Github space. There is no package distribution for this library and you will have to clone it, build and install it in your system. However Debian packages of SDRangel contain a pre-compiled version of this library.
 
 If you use your own location for libmirisdr-4 install directory you need to specify library and include locations with cmake. For example with `/opt/install/libmirisdr` the following defines must be added on `cmake` command line:
 
@@ -196,7 +196,7 @@ Then in a terminal do:
   - `sudo dpkg -i sdrangel_vx.y.z-1_amd64.deb` where x.y.z is the version number
   - `sudo apt-get -f install` this will install missing dependencies
     
-The software is installed in `\opt\sdrangel` you can start it from the command line with:
+The software is installed in `/opt/sdrangel` you can start it from the command line with:
   - `/opt/sdrangel/bin/sdrangel`
 
 <h1>Software build</h1>

plugins/channelrx/demodam/readme.md

@@ -0,0 +1,43 @@
+<h1>AM demodulator plugin</h1>
+
+<h2>Introduction</h2>
+
+This plugin can be used to listen to a narrowband amplitude modulated signal. By "narrowband" it means that the bandwidth can vary from 1 to 40 kHz.
+
+<h2>Interface</h2>
+
+![AM Demodulator plugin GUI](../../../doc/img/AMDemod_plugin.png)
+
+<h3>1: Frequency shift from center frequency of reception direction</h3>
+
+The "+/-" button on the left side toggles between positive and negative shift.
+
+<h3>2: Frequency shift from center frequency of reception value</h3>
+
+Use the wheels to adjust the frequency shift in Hz from the center frequency of reception. 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 at the digit position.
+
+<h3>3: Channel power</h3>
+
+Average total power in dB relative to a +/- 1.0 amplitude signal received in the pass band.
+
+<h3>4: Audio mute</h3>
+
+Use this button to toggle audio mute for this channel. The button will light up in green if the squelch is open. This helps identifying which channels are active in a multi-channel configuration.
+
+<h3>5: Level meter in dB</h3>
+
+  - top bar (green): average value
+  - bottom bar (blue green): instantaneous peak value
+  - tip vertical bar (bright green): peak hold value
+
+<h3>6: RF bandwidth</h3>
+
+This is the bandwidth in kHz of the channel signal before demodulation. It can be set continuously in 1 kHz steps from 1 to 40 kHz.
+
+<h3>7: Volume</h3>
+
+This is the volume of the audio signal from 0.0 (mute) to 10.0 (maximum). It can be varied continuously in 0.1 steps using the dial button.
+
+<h3>8: Squelch threshold</h3>
+
+This is the squelch threshold in dB. The average total power received in the signal bandwidth before demodulation is compared to this value and the squelch input is open above this value. It can be varied continuously in 0.1 dB steps from 0.0 to -100.0 dB using the dial button.

plugins/channelrx/demodnfm/readme.md

@@ -6,48 +6,58 @@ This plugin can be used to listen to a narrowband FM modulated signal. By "narro
 
 <h2>Interface</h2>
 
-![NFM Demodulator plugin GUI](/doc/img/NFMdemod_plugin.png)
+![NFM Demodulator plugin GUI](../../../doc/img/NFMdemod_plugin.png)
 
-<h3>1: Frequency shift from center frequency of reception</h3>
+<h3>1: Frequency shift from center frequency of reception direction</h3>
 
-Use the wheels to adjust the frequency shift in Hz from the center frequency of reception. Use the "+/-" button on the left side to toggle between positive and negative shift.
+The "+/-" button on the left side toggles between positive and negative shift.
 
-<h3>2: Channel power</h3>
+<h3>2: Frequency shift from center frequency of reception value</h3>
 
-Total power in dB relative to a +/- 1.0 amplitude signal received in the pass band.
+Use the wheels to adjust the frequency shift in Hz from the center frequency of reception. 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 at the digit position.
 
-<h3>3: RF bandwidth</h3>
+<h3>3: Channel power</h3>
+
+Average total power in dB relative to a +/- 1.0 amplitude signal received in the pass band.
+
+<h3>4: Level meter in dB</h3>
+
+  - top bar (green): average value
+  - bottom bar (blue green): instantaneous peak value
+  - tip vertical bar (bright green): peak hold value
+
+<h3>5: RF bandwidth</h3>
 
 This is the bandwidth in kHz of the channel signal before demodulation. It can be set in steps as 5, 6.25, 8.33, 10, 12.5, 15, 20, 25 and 40 kHz.
 
-<h3>4: AF bandwidth</h3>
+<h3>6: AF bandwidth</h3>
 
 This is the bandwidth of the audio signal in kHz (i.e. after demodulation). It can be set in continuous kHz steps from 1 to 20 kHz.
 
-<h3>5: Volume</h3>
+<h3>7: Volume</h3>
 
 This is the volume of the audio signal from 0.0 (mute) to 10.0 (maximum). It can be varied continuously in 0.1 steps using the dial button.
 
-<h3>6: Squelch threshold</h3>
+<h3>8: Squelch threshold</h3>
 
-This is the squelch threshold in dB. The total power received in the signal bandwidth before demodulation is compared to this value and the squelch input is open above this value. It can be varied continuously in 0.1 dB steps from 0.0 to -100.0 dB using the dial button.
+This is the squelch threshold in dB. The average total power received in the signal bandwidth before demodulation is compared to this value and the squelch input is open above this value. It can be varied continuously in 0.1 dB steps from 0.0 to -100.0 dB using the dial button.
 
-<h3>7: Squelch gate</h3>
+<h3>9: Squelch gate</h3>
 
 This is the squelch gate in milliseconds. The squelch input must be open for this amount of time before the squelch actually opens. This prevents the opening of the squelch by parasitic transients. It can be varied continuously in 10ms steps from 10 to 500ms using the dial button.
 
-<h3>8: CTCSS on/off</h3>
+<h3>10: CTCSS on/off</h3>
 
 Use the checkbox to toggle CTCSS activation. When activated it will look for a tone squelch in the demodulated signal and display its frequency (see 10). 
 
-<h3>9: CTCSS tone</h3>
+<h3>11: CTCSS tone</h3>
 
 This is the tone squelch in Hz. It can be selected using the toolbox among the usual CTCSS values and `--` for none. When a value is given and the CTCSS is activated the squelch will open only for signals with this tone squelch.
 
-<h3>10: CTCSS tone value</h3>
+<h3>12: CTCSS tone value</h3>
 
 This is the value of the tone squelch received when the CTCSS is activated. It displays `--` if the CTCSS system is de-activated.
 
-<h3>11: Audio mute</h3>
+<h3>13: Audio mute</h3>
 
 Use this button to toggle audio mute for this channel. The button will light up in green if the squelch is open. This helps identifying which channels are active in a multi-channel configuration.

plugins/channelrx/demodssb/readme.md

@@ -0,0 +1,64 @@
+<h1>SSB/DSB demodulator plugin</h1>
+
+<h2>Introduction</h2>
+
+This plugin can be used to listen to a single sideband or double sidebands modulated signals. 
+
+<h2>Interface</h2>
+
+![SSB Demodulator plugin GUI](../../../doc/img/SSBDemod_plugin.png)
+
+<h3>1: Frequency shift from center frequency of reception direction</h3>
+
+The "+/-" button on the left side toggles between positive and negative shift.
+
+<h3>2: Frequency shift from center frequency of reception value</h3>
+
+Use the wheels to adjust the frequency shift in Hz from the center frequency of reception. 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 at the digit position.
+
+<h3>3: Channel power</h3>
+
+Average total power in dB relative to a +/- 1.0 amplitude signal received in the pass band.
+
+<h3>4: Monaural/binaural toggle</h3>
+
+  - Monaural: the scalar signal is routed to both left and riht audio channels
+  - Binaural: the complex signal is fed with the real part on the left channel and the imaginary part to the rigth channel
+  
+<h3>5: Invert left and right channels</h3>
+
+Inverts left and right audio channels. Useful in binaural mode only.
+
+<h3>6: SSB/DSB demodulation</h3>
+
+Toggles between SSB (icon with one sideband signal) and DSB (incon with double sidebands signal)
+
+<h3>7: Level meter in dB</h3>
+
+  - top bar (green): average value
+  - bottom bar (blue green): instantaneous peak value
+  - tip vertical bar (bright green): peak hold value
+
+<h3>8: Span</h3>
+
+Signal span (i.e. sample rate) befor demodulation
+
+<h3>9: Bandwidth</h3>
+
+This is the upper limit in kHz of the signal filtered after demodulation. 
+
+<h3>10: Bandwidth</h3>
+
+SSB only: this is the lower limit in kHz of the signal filtered after demodulation. 
+
+<h3>11: Volume</h3>
+
+This is the volume of the audio signal from 0.0 (mute) to 10.0 (maximum). It can be varied continuously in 0.1 steps using the dial button.
+
+<h3>12: Audio mute</h3>
+
+Use this button to toggle audio mute for this channel. The button will light up in green if the squelch is open. This helps identifying which channels are active in a multi-channel configuration.
+
+<h3>13: Spectrum display</h3>
+
+This is the spectrum display of the demodulated signal (SSB) or translated signal (DSB)