Hi gang.

This is a new version of PocketDigi. There are two new modems implemented - Throb/ThrobX and Olivia/Contestia/RTTYM. Both of them have not been optimized for best S/N yet, but seem to work well.

The Olivia modem has been adopted from the code by Pawel Jalocha, but simplified. I have removed the receive input processor, which does kind of channel equalization. I actually do not think that Olivia decodes better than MFSK16, but Olivia is much more easier to tune. I wonder whether anyone will ever use the Throb/ThrobX modems.

If the microphone input is overloaded, the waterfall line will be marked by magenta stripes now. I did not know myself that my device gets overloaded by the Warbler TRX until I added this feature. The overload must have added considerable distortion to the signal. If you experience it, add an external resistor divider to the microphone cable.

Please report the bugs, annoyances, whishes etc. If I do not know about the bugs, I would not fix them. Thanks.

Excerpt from ChangeLog:

- Added OLIVIA/CONTESTIA/RTTYM modes. Initial implementation without channel equalization.
- The three new modes tested for compatibility against MULTIPSK 4.1.2
- Known issue of THROB: AFC does not work correctly
- Overload indication. Magenta stripes are drawn over the waterfall if mic input is overdriven.
- Fixed <NULL> bug in RTTY
- Fixed CW TX speed setting problem.
- Fixed problem of hanging CW TX at slow speeds.
- RTTY filters changed from IIR to FIR, which are faster on a fixed point CPU
- Added THROB/THROBX modes
- Enabled reverse for MFSK16
- Premliminary port of Feld Hell. Only TX enabled, paper tabe control is still missing for RX.
- Added setting of TX prefetch sound card buffers. If experiencing rattling sound during TX, increasing number of prefetch buffers may help
- Adding error message boxes to report problems with sound card. It shall clarify, whether some of the OEMs are lazy to support duplex sound input/output

73, Vojtech OK1IAK

Posted by Vojtech Bubnik OK1IAK 2007-01-14

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