The filters in WRplus 1.04
(July 6 2011)
Test method.


When the test file is played with WRplus-1.04, the screen may look like figure 1. It depends of course how the parameters in WRplus are set.

Fig 1. WRplus-1.04 running sim1.wav.

The loudspeaker output from WRplus-1.04 sounds like this: sim1-wrplus.mp3 (558600 bytes.) The on-off keyed signal is at a level that is similar to the noise floor level in the beginning and end of the file where the data comes from an old Perseus recording.

There close range spurs that do quite not match the performance of modern hardware. The tested WRplus version was obtained by installing WRplus_1.04 which was downloaded January 7 2011.

The wide range spurs that were present in the previous release are not present here, but the close range spurs are still the same. Results are much better than the test results for the previous version, WRplus_1.03 because the close range spurs often fall in a frequency range where modulation and sideband noise of the strong signal would dominate. The details of the loudspeaker output are shown in figures 2 and 3 which are waterfall graphs produced by Linrad with sim1-wrplus.mp3 as the input (before conversion to mp3).

Fig 2.The loudspeaker output from WRplus-1.04 when running the test recording sim1.wav. This waterfall graph is produced by Linrad with the loudspeaker output from WRplus-1.04 as input.

Fig 3.The loudspeaker output from WRplus-1.04 This the same as figure 2 at a 10 times higher waterfall speed. The time when the signal sweeps across the passband is well visible as well as a couple of fairly weak spurs.

The loudspeaker output of WRplus-1.04 on an oscilloscope looks like figures 4 and 5 at different X-axis magnification.

Figs 4 and 5The loudspeaker output from WRplus-1.04 in the time domain when the signal sweeps across the filter.

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