User's Guide

WR-3700 Series User’s Guide

DSP

The WiNRADiO Spectrum Monitor internal receiver (WR-3700i-DSP) has a DSP fitted to

allow digital processing of the audio from the receiver. This gives the receiver the ability to

filter the audio, decode digital data and perform other processing on the audio signal.

In-built DSP applets allow recording and playback from the Sound Recorder feature. For

customer specific applications, developers' information is available to allow new DSP

software to be added to the basic WiNRADiO Spectrum Monitor software.

Using a DSP Applet

All installed DSP applets appear in the 'DSP' menu in WiNRADiO. To start up an applet,

select the appropriate applet from the menu. A window will appear allowing you to setup

various parameters associated with the applet. All WiNRADiO functions can still be used

while the applet is still running.

Adding a DSP Applet

To add a new applet, copy the file into the directory where WiNRADiO is installed. Applet

files have a .DSP extension. If WiNRADiO is already running, close it down first.

When WiNRADiO starts up, it will load all the DSP applets found in its directory and add

the applet's functions to the DSP menu.

Signal Conditioner Applet

The WiNRADiO Spectrum Monitor software comes supplied with a DSP applet that

provides high performance post-demodulation audio filtering, which is particularly useful

when receiving CW and SSB signals, and in some cases (for example HF broadcast) AM.

To run this DSP applet, select corresponding item in the DSP menu (ie. DSP - Start applet -

Signal Conditioner). The following window appears on the screen:

This is the description of the controls:

1. Bandpass Filter enables the audio ‘brick wall’ band pass filter. See ‘6’ and ‘7’ to tune

the filter response in real time.

2. Noise Reduction enables adaptive random noise filtering. This option works better for

higher signal-to-noise ratios.

3. Auto Notch enables adaptive automatic heterodyne cancellation. The Auto Notch

eliminates multiple tones form the audio spectrum. This is very useful to cancel ‘carrier

signals’, while receiving SSB-modulated signals.

4. Marker Tone activates generation of audible tone with its frequency equal to the centre

frequency of the pass band of the filter. This is useful guide for tunning-in on CW

signals. A complementary visual guide is the real time FFT display (8).