7 Audio
97
Chapter 7
7 Audio
The Audio-denoiser-menu (aud:-menu) is activated with the command AUdio. The
command prompt takes the form aud: .
The following commands are available in the aud:-menu:
Bandwith, Center, CWfilter, DD, Delay, Help, Invert, Notch,
Peak, Quit, Through, TOne.
All other (normal) commands are not available in the aud:-menu! Quit or DD exit the
aud:-menu.
The commands of the aud:-menu in detail:
7.1 Bandwidth
Default setting: 300
Parameter: X 30... 1000, Bandwith in Hz.
Adjusts the -6 dB bandwidth of the CW-filter continuously between 30 and 1000 Hz.
(Refer also to command CWfilter, chapter 7.3).
7.2 Center
Default setting: 1400
Parameter: X 300... 2700, center frequency of the CW-filter.
Sets the center frequency of the CW-filter continuously between 300 and 2700 Hz. (Refer
also to command CWfilter, chapter 7.3 and the command CWTerm, chapter 6.30).
The Center command also adjusts the audio frequency of the CW-Terminal (chapter
6.30) of the PTC-IIIusb send and receive sides. (In firmware releases prior to version
1.12, the CW-Terminal used the current Mark-frequency, which sometimes was not
particularly suitable).
7.3 CWfilter
Activates the CW-filter, using the center frequency set by the Center command, and the
bandwidth set by the Bandwidth command.
The filter is designed as FIR with a linear phase-change, so that even with a bandwidth of
30 Hz it does not ring. The transfer function has not been designed for maximum edge
steepness, but a shape delivering a signal easily readable for the human ear, and the best
signal/noise ratio possible.
To Next Page
