Difference between revisions of "Ghpsdr3 protocols"

Latest revision as of 10:07, 11 April 2011

server HPSDR hardware server

The HPSDR server handles communications with the HPSDR hardware and is designed to work with multiple receivers either on a single Mercury card or multiple Mercury cards. It demultiplexes the I/Q samples into separate streams for each receiver. The hardware server listens on port 11000 for TCP connections from clients. The client (dspserver) makes a connection request through port 11000, and sets up a TCP socket on on port 12000+rx, on which it sends commands to the server. IQ data is sent over UDP.

Commands to server

The server recognizes a number of commands, shown below. It sends a response to the client after parsing each command. The possible responses are also shown.

• • attach rx

  attach client to receiver rx

  The receiver number rx is an integer from 0 to 3

  example: attach 0

  response:

  "Error: Client is already attached to receiver" (Receiver rx is already attached.)

  "Error: Invalid Receiver" (rx is higher than number of receivers specified on the command line.)

  "Error: Receiver in use"

  "OK" <sample Rate>

  • detach rx

  detach client from receiver rx

  example: detach 0

  response:

  "Error: Client is not attached to receiver"

  "Error: Invalid Receiver" (rx is higher than number of receivers specified on the command line.)

  "Error: Not owner of receiver"

  • frequency f

  Set attached receiver frequency to the integer frequency f (Hz)

  example: frequency 7056000

  response:

  "Error: Client is not attached to receiver"

  "Error: Invalid Receiver" (rx is higher than number of receivers specified on the command line.)

  "OK"

  • start iq port

  start sending I & Q samples for the attached receiver to the UDP port specified

  example: start iq 13000

  response:

  "Error: Invalid Command"

  "OK"

  • start bandscope port

  start sending bandscope samples to the UDP port specified

  example start bandscope 12500

  response:

  "Error: Invalid Command"

  "OK"

  • stop iq

  stop sending I & Q data to the attached receiver

  response:

  "Error: Invalid Command"

  "OK"

  • stop bandscope

  stop sending bandscope data

  response:

  "Error: Invalid Command"

  "OK"

A typical exchange would be:

Note that there are currently no commands to control setting the number of receivers, preamp, dither, random, samplerate or clock sources. As this was developed to support multiple receivers, I decided to not allow clients to change these as they would be changed for all receivers. They are all controlled by command line arguments when running the server.

I / Q data stream

The I/Q samples are accumulated in the server until there are 1024 I/Q samples to send. The samples are sent in 512 byte UDP packets, to the port specified in the 'start iq' message, with 12 byte header and up to 500 bytes of I/Q samples.

The UDP packet header contains:

• 8 byte sequence number (At present, the Windows port uses only a 4 byte sequence number. Until this is changed, both server and dspserver must be running on Windows or Linux, not one on Windows and one on Linux.)
• 2 byte offset within this set of samples
• 2 byte length of samples

Following the header, the I and Q samples are sent, first 1024 float I samples, followed by 1024 float Q samples.

server command line options (default value)

• --receivers <1..4>
• --samplerate [48000|96000|192000]
• --dither [off|on]
• --random [off|on]
• --preamp [off|on]
• --10mhzsource [atlas|penelope|mercury]
• --122.88mhzsource [penelope|mercury]
• --micsource [janus|penelope]
• --class [E|other]

Example:

./server --receivers 4 --samplerate 96000 --dither on --10mhzsource atlas

Note: As an experiment, there is also a softrockserver that supports the same protocol with the restriction that there is only one receiver and it uses the USB/si570 interface to control the frequency. The I/Q samples are taken from an Audio device specified on the command line.

dspserver

dspserver is a client to the hardware server. In turn, it is the server for another client, typically a GUI, such as jmonitor. It provides a dsp processing service using DttSP. Typically one dspserver is started for each receiver. The dspserver listens for client TCP connections on port 8000+rx. i.e. rx0 listens on 8000, rx1 listens on 8001, etc. The client sends commands to the dspserver and dspserver sends data packets to its client on this same port. The first byte of each packet sent to the client identifies the type of data in the packet.

• 0 spectrum data
• 1 audio data

Commands to dspserver

• • getSpectrum points

  Request points of spectrum data. The value sent for each point is an 8 bit unsigned integer. If the calculated spectrum contains more points than the client requests, adjacent points are combined, and the highest value in the group is sent.

  Example: getSpectrum 480

  • setFrequency f

  Set the receiver frequency to f, in Hz

  example: setFrequency 7056000

  • setMode mode

  mode is an integer specifying the type of demodulation

  • • 0 - LSB
    • 1 – USB
    • 2 – DSB
    • 3 – CWL
    • 4 – CWH
    • 5 – FM
    • 6 – AM
    • 7 - DIGU
    • 8 - SPEC
    • 9 - DIGL
    • 10 - SAM
    • 11 – DRM

  example: setMode 0

  • setFilter low high

  Set filter cutoff frequencies

  For LSB, both frequencies are negative

  For USB, both frequencies are positive

  For AM or DSP, typically low is negative and high is positive

  example: setFilter 150 3450

  • setAGC n

  Select AGC time

  • • 1 - LONG
    • 2 - SLOW
    • 3 - MEDIUM
    • 4 - FAST

  example: setAGC 3

  • setNR n

  Set noise reduction

  • • 0 - off
    • 1 - on
  • setNB n

  Set noise blanker

  • • 0 - off
    • 1 - on
  • setANF n

  Set automatic noise filter

  • • 0 - off
    • 1 - on
  • setRXOutputGain gain

  Set receiver audio output level to the value gain

  The value is a floating point number in the range 0 to 1.

  example: setRXOutputGain 0.5

  • startAudioStream buffer size

  start sending audio data.

  buffer size is optional, and is an integer, typically 480.

  If omitted, a value of 480 is used.

  • stopAudioStream

  stop sending the audio data.

data packet format Each packet has a 48 byte header.

Sample rate and Meter reading numbers are in ASCII characters.

Audio data is sent as one channel of 8-bit aLaw samples at 8000 samples per second.

dspserver command line options (default value)

• --soundcard SANTA_CRUZ, AUDIGY_2_ZS, MP3_PLUS, EXTIGY,

  DELTA_44, FIREBOX, EDIROL_FA_66, HPSDR

• --receiver 0, 1, 2, or 3
• --server IP address 127.0.0.1 (this is "localhost")
• --offset ???

summary of port usage