DSD demod: NXDN support documentation

debian/changelog

@@ -1,3 +1,11 @@
+sdrangel (4.0.1-1) unstable; urgency=medium
+
+  * DSD demod: added NXDN support
+  * DATV demod: include it only if FFmpeg > 3.1 is installed
+  * Fixes for Arch. Manual merge of pull request #183
+
+ -- Edouard Griffiths, F4EXB <f4exb06@gmail.com>  Sat, 23 Jun 2018 09:14:18 +0200
+  
 sdrangel (4.0.0-1) unstable; urgency=medium
 
   * Finalization of REST API and server instance

plugins/channelrx/demoddsd/dsddemodplugin.cpp

@@ -27,7 +27,7 @@
 
 const PluginDescriptor DSDDemodPlugin::m_pluginDescriptor = {
 	QString("DSD Demodulator"),
-	QString("4.0.0"),
+	QString("4.0.1"),
 	QString("(c) Edouard Griffiths, F4EXB"),
 	QString("https://github.com/f4exb/sdrangel"),
 	true,

plugins/channelrx/demoddsd/readme.md

@@ -8,9 +8,6 @@ This plugin uses the [DSDcc](https://github.com/f4exb/dsdcc) library that has be
   - dPMR: Another ETSI standard at slower rate (2400 Baud / 6.25 kHz) and FDMA
   - D-Star: developed and promoted by Icom for Amateur Radio customers.
   - Yaesu System Fusion (YSF): developed and promoted by Yaesu for Amateur Radio customers. Voice full rate with DV serial devices is not supported
-
-It can only detect the following standards (no data, no voice):
-
   - NXDN: A joint Icom (IDAS) and Kenwood (Nexedge) standard with 2400 and 4800 Baud versions.
 
 The modulation and standard is automatically detected and switched depending on the Baud rate chosen.
@@ -294,6 +291,89 @@ This displays a summary of FICH (Frame Identification CHannel) block data. From
 
 This is the unique character string assigned to the device by the manufacturer.
 
+<h4>A11.5: NXDN status display</h4>
+
+There are 3 display formats depending on the kind of transmission called RF channel in the NXDN system.
+
+<h5>A11.5.1: RCCH RF channel display</h5>
+
+This is the control channel used in trunked systems and is usually sent continuously.
+
+![DSD NXDN RTDCH status](../../../doc/img/DSDdemod_plugin_nxdn_rcch_status.png)
+
+<h6>A11.5.1.1: RF channel indicator</h5>
+
+This is `RC` for RCCH
+
+<h6>A11.5.1.2: RAN number</h5>
+
+This is the RAN number (0 to 63) associated to the transmission. RAN stands for "Radio Access Number" and for trunked systems this is the site identifier (Site Id) modulo 64.
+
+<h6>A11.5.1.3: Last message type code</h5>
+
+This is the type code of the last message (6 bits) displayed in hexadecimal. The complete list is found in the NXDN documentation `NXDN TS 1-A Version 1.3` section 6.
+
+<h6>A11.5.1.4: Location Id</h5>
+
+This is the 3 byte location Id associated to the site displayed in hexadecimal
+
+<h6>A11.5.1.5: Services available flags</h5>
+
+This is a 16 bit collection of flags to indicate which services are available displayed in hexadecimal. The breakdown is listed in the NXDN documentation `NXDN TS 1-A Version 1.3` section 6.5.33. From MSB to LSB:
+
+  - first nibble (here `B`):
+    - `b15`: Multi-site service 
+    - `b14`: Multi-system service 
+    - `b13`: Location Registration service 
+    - `b12`: Group Registration Service
+  - second nibble (here `3`):
+    - `b11`: Authentication Service 
+    - `b10`: Composite Control Channel Service 
+    - `b9`: Voice Call Service 
+    - `b8`: Data Call Service
+  - third nibble (here `C`):
+    - `b7`: Short Data Call Service 
+    - `b6`: Status Call & Remote Control Service
+    - `b5`: PSTN Network Connection Service
+    - `b4`: IP Network Connection Service
+  - fourth nibble (here `0`) is spare
+
+<h5>A11.5.2: RTCH or RDCH RF channel display</h5>
+
+This is the transmission channel either in a trunked system (RTCH) or conventional system (RDCH).
+
+![DSD NXDN RTDCH status](../../../doc/img/DSDdemod_plugin_nxdn_rtdch_status.png)
+
+<h6>A11.5.2.1: RF channel indicator</h5>
+
+It can be either `RT` for RTCH or `RD` for a RDCH channel
+
+<h6>A11.5.2.2: RAN number</h5>
+
+This is the RAN number (0 to 63) associated to the transmission. RAN stands for "Radio Access Number" and has a different usage in conventional or trunked systems:
+
+  - Conventional (RDCH): this is used as a selective squelch. Code `0` means always unmute.
+  - Trunked (RTCH): this is the site identifier (Site Id) modulo 64.
+
+<h6>A11.5.2.3: Last message type code</h5>
+
+This is the type code of the last message (6 bits) displayed in hexadecimal. The complete list is found in the NXDN documentation `NXDN TS 1-A Version 1.3` section 6.
+
+<h6>A11.5.2.4: Source Id</h5>
+
+This is the source of transmission identification code on two bytes (0 to 65353) displayed in decimal.
+
+<h6>A11.5.2.5: Destination Id</h5>
+
+This is the destination of transmission identification code on two bytes (0 to 65353) displayed in decimal. It is prefixed by a group call indicator:
+
+  - `G`: this is a group call
+  - `I`: this is an individual call
+
+<h5>A11.5.3: Unknown or erroneous data display</h5>
+
+In this case the display is simply "RU" for "unknown"
+
 <h3>B section: digital</h3>
 
 <h4>B.1: FM signal scope</h4>