Showing device capabilities¶

This is the default behavior. It will open the frontend and show what capabilities it supports and what's the version of the DVB API.

$ dvb-fe-tool
Device DRXK DVB-C DVB-T (/dev/dvb/adapter0/frontend0) capabilities:


     CAN_FEC_1_2


     CAN_FEC_2_3


     CAN_FEC_3_4


     CAN_FEC_5_6


     CAN_FEC_7_8


     CAN_FEC_AUTO


     CAN_GUARD_INTERVAL_AUTO


     CAN_HIERARCHY_AUTO


     CAN_INVERSION_AUTO


     CAN_MUTE_TS


     CAN_QAM_16


     CAN_QAM_32


     CAN_QAM_64


     CAN_QAM_128


     CAN_QAM_256


     CAN_RECOVER


     CAN_TRANSMISSION_MODE_AUTO
DVB API Version 5.10, Current v5 delivery system: DVBC/ANNEX_A
Supported delivery systems:


    [DVBC/ANNEX_A]


     DVBC/ANNEX_C


     DVBT

Setting the delivery system¶

Some devices (like the above example) supports multiple delivery systems. Older DVB applications might not be able to switch from one delivery system to another one, as this feature were added only on DVB API version 5.5.

This feature allows one to use those legacy applications.

$ dvb-fe-tool -d dvbc/annex_c
Changing delivery system to: DVBC/ANNEX_C

Getting the current frontend settings¶

The tool can also be used to get the current settings. In this case, it will open the frontend at read-only mode, allowing it to be called while some other digital TV application is running.

$ dvb-fe-tool -g
FREQUENCY = 573000000
MODULATION = QAM/256
INVERSION = AUTO
SYMBOL_RATE = 5217000
INNER_FEC = NONE
DELIVERY_SYSTEM = DVBC/ANNEX_A

Monitoring the frontend¶

The dvb-fe-tool can also be used to monitor a DVB frontend statistics without touching on the device, using the --femon (or -m) parameter. The typical usage is to be able to read the statistics while some other DVB program or application is in use.

On this mode, it will keep printing the frontend statistics on every second, until the program is aborted with CTRL-C:

For example, while dvbv5-zap is tuning some channel, it will produce:

$ dvb-fe-tool --femon
Lock   (0x1f) Quality= Good Signal= 100.00% C/N= 36.40dB UCB= 370 postBER= 28.0x10^-6 PER= 0
Lock   (0x1f) Quality= Good Signal= 100.00% C/N= 36.80dB UCB= 370 postBER= 25.3x10^-6 PER= 0
Lock   (0x1f) Quality= Good Signal= 100.00% C/N= 36.30dB UCB= 370 postBER= 25.7x10^-6 PER= 0
Lock   (0x1f) Quality= Good Signal= 100.00% C/N= 36.30dB UCB= 370 postBER= 28.4x10^-6 PER= 0
Lock   (0x1f) Quality= Good Signal= 100.00% C/N= 36.50dB UCB= 370 postBER= 26.5x10^-6 PER= 0
Lock   (0x1f) Quality= Good Signal= 100.00% C/N= 36.50dB UCB= 370 postBER= 26.9x10^-6 PER= 0
Lock   (0x1f) Quality= Good Signal= 100.00% C/N= 36.20dB UCB= 370 postBER= 28.6x10^-6 PER= 0
Lock   (0x1f) Quality= Good Signal= 100.00% C/N= 36.70dB UCB= 370 postBER= 26.7x10^-6 PER= 0
Lock   (0x1f) Quality= Good Signal= 100.00% C/N= 36.80dB UCB= 370 postBER= 23.3x10^-6 PER= 0
Lock   (0x1f) Quality= Good Signal= 100.00% C/N= 36.50dB UCB= 370 postBER= 26.7x10^-6 PER= 0

If the standard error device is the console, the messages will be colored according with the signal quality.

The presented statistics types and unities will depend on the ones that the hardware you're using support. So, it may vary from hardware to hardware.

On this mode, it also supports to output an audible signal if the quality is good, using the '-A' parameter.

Please notice that, on modern Linux systems, the system audio should be enabled at your window manager and the audio theme should be set to produce an audio when BELL (character) is sent to the terminal.

NOTE:¶

C/N on the above stats means Carrier to Noise ratio. This is the Signal to Noise ratio measured at the pilot carrier or just the Signal to Noise ratio for modulation types where just one carrier is used, like DVB-C or DVB-S.