diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/example.ini | 94 |
1 files changed, 77 insertions, 17 deletions
diff --git a/doc/example.ini b/doc/example.ini index 0f5dfe2..9cdfe03 100644 --- a/doc/example.ini +++ b/doc/example.ini @@ -20,33 +20,68 @@ filename=/dev/stderr transport=file source=/dev/stdin +; When the end of file is reached, it is possible to rewind it +loop=0 + ; When recieving data using ZeroMQ, the source is the URI to be used ;transport=zeromq ;source=tcp://localhost:8080 -loop=1 [modulator] ; Gain mode: 0=FIX, 1=MAX, 2=VAR +; +; Mode 0 (FIX) uses a fixed factor and is really not recommended. It is more +; useful on an academic perspective for people trying to understand the DAB +; modulation. +; +; Mode 1 (MAX) is the normalization of every OFDM symbol. No overshoot, no +; truncating, but varying output power (around 3dB) which might not be the best +; for some power amplifier. The output samples are limited to a magnitude +; of 32768. +; +; Mode 2 (VAR) uses the method specified in ETSI 300 798. This method +; normalizes to 4 times the standard deviation for an approximation of the RMS +; power. So around 6/100000 samples will be truncated and will introduce some +; really minor distortion. But this mode also maximizes the output power. This +; is the gain mode recommended for real world operation as it is based on a DAB +; standard; the only difference is that ODR-DabMod uses a better resolution +; with 16 bits instead of 8 bits. gainmode=2 ; Transmission mode ; If not defined, take the mode from ETI ;mode=2 -; Set to 0 to disable CicEqualiser -dac_clk_rate=0 - +; The digital gain is a value that is multiplied to each sample. It is used +; to tune the chain to make sure that no non-linearities appear up to the +; USRP daughterboard programmable gain amplifier (PGA). +; If there is clipping, the spectral quality of the signal will quickly deteriorate, +; and wide-band noise will be generated. +; +; Be aware that there is a dependency with resampling. digital_gain=1.0 -; Output sample rate +; Output sample rate. Values other than 2048000 enable +; resampling. +; Warning! digital_gain settings are different if resampling +; is enabled or not ! rate=2048000 +; CIC equaliser for USRP1 and USRP2 +; Set to 0 to disable CicEqualiser +; when set to 400000000, an additional USRP2 check is enabled. +; See DabModulator.cpp line 186 +dac_clk_rate=0 + ; The USRP1 does not have flexible clocking, you will need ;rate=3200000 ; and ;dac_clk_rate=128000000 [firfilter] +; The FIR Filter can be used to create a better spectral quality. +; The filter taps can be calculated with the python script +; doc/fir-filter/generate-filter.py enabled=0 filtertapsfile=simple_taps.txt @@ -55,15 +90,32 @@ filtertapsfile=simple_taps.txt output=uhd [fileoutput] +; The file output writes I/Q float values (i.e. complex float) +; to the file. The I and Q samples can take values up to +; 100000 in absolute magnitude with gainmode FIX. +; With gainmode VAR, they should never exceed 50000. +; With gainmode MAX, thet are limited to 32767. filename=/dev/stdout [uhdoutput] -; For a USRP B100: +; The UHD output can be directly used with the Ettus USRP devices +; +; You have to set master_clock_rate to a multiple of the +; sample_rate. Ideally, it should be +; master_clock_rate = 4 * sample_rate +; or even a higher factor. +; +; Settings for a USRP B100: device=master_clock_rate=32768000,type=b100 txgain=2 -; Try with small gain values +; Try first with small gain values +; Also set rate to 2048000 ; For the B200 +; More information and measurements available on: +; http://opendigitalradio.org/index.php/USRP_B200_Measurements +; +; Settings: ;device=master_clock_rate=20480000,type=b200 ;txgain=40 ; The B200 needs larger gains (up to 89dB) but, @@ -73,43 +125,51 @@ txgain=2 ; From the B200 User Manual ; http://files.ettus.com/uhd_docs/manual/html/usrp_b200.html -; TODO: measure the RF quality with different values of master_clock_rate: -; 10240000 -; 20480000 -; 30720000 -; 32768000 -; and other values ; For the USRP1 ;device=type=usrp1 ; the usrp1 can have two daughterboards, the subdevice parameter allows you ; to choose which one to use ;subdevice=A:0 +; The USRP1 doesn't support master_clock_rate, you need to enable resamping + -; you must specify either frequency or channel +; You must specify either frequency or channel, but not both. ;frequency=234208000 channel=13C +; The reference clock to use. ; possible values : internal, external, MIMO refclk_source=internal +; The reference one pulse-per second to use ; possible values : none, external, MIMO pps_source=none -; behaviour when external clock reference lock lost +; Behaviour when external clock reference lock lost ; possible values: ignore, crash behaviour_refclk_lock_lost=ignore ; Used for SFN with the UHD output [delaymanagement] + +; Enable handling of timestamps for SFN synchronous=0 -; whether to mute the TX when incoming frames have no timestamp +; Whether to mute the TX when incoming frames have no timestamp mutenotimestamps=0 -; choose between fixed and dynamic offset definition +; Choose between fixed and dynamic offset definition +; fixed defines an offset in this file that cannot be changed while +; the modulator runs. +; +; dynamic reads the offset from a file, and if the value changes, +; the chain does a re-sync. management=dynamic fixedoffset=0.002 + +; The file should contain a single floating point value, written +; in ASCII (it's human-readable, not binary) dynamicoffsetfile=modulator_offset |