Rowetel

Codec 2 at 3200 bit/s

By david, on September 17th, 2012

For the last few weeks I have been working on integrating the new LPC post filter into Codec 2 as part of some paid Codec 2 work to develop higher quality, higher bit rate modes for VOIP. Although I actually had a budget of up to 6400 bit/s, much to my embarrasment I couldn’t work . . . → Read More: Codec 2 at 3200 bit/s

LPC Post Filter for Codec 2

By david, on September 4th, 2012

This post describes a post filter that significantly improves the quality of Codec 2.

For the past month I have been working on developing a high quality, higher bit rate version of Codec 2. The target is 4000 bit/s with speech quality similar to todays 8000 bit/s codecs. The application is VOIP, rather than . . . → Read More: LPC Post Filter for Codec 2

Codec 2 wins the ARRL Technical Innovation Award

By david, on August 2nd, 2012

I’ve won the ARRL Technical Innovation Award for 2012 for my Codec 2 work.

When I first became interested in Ham Radio as a 12 year old in the late 70′s my grandfather bought me the 1979 ARRL handbook. Quite an honor to one day be contributing back to this fine hobby that was my start . . . → Read More: Codec 2 wins the ARRL Technical Innovation Award

Web Site Updates

By david, on May 11th, 2012

I am about to head to Dayton for the Hamvention, so took the opportunity to bring my web site up to date. The Codec 2 page includes our latest plans on building a Linux/Windows GUI Application for HF Digital Voice, has updates on recent algorithm developments, links to conference videos, and lots of figures explaining . . . → Read More: Web Site Updates

ISIF award for Dili Village Telco

By david, on May 9th, 2012

This is somewhat old news but last September Fongtil and I won an award for our work on the Dili Village Telco. Here is the ISIF press release. We were selected from a group of about 50 ISIF funded projects for the award. Here is a photo of Lemi (2nd from right) accepting . . . → Read More: ISIF award for Dili Village Telco

FDMDV Modem Page

By david, on May 7th, 2012

I have added a FDMDV modem page to this web site, plus typed up a README_fdmdv.txt that explains all the files related to the modem and how to use them.

This modem was “lost” a few years ago as the initial implementation was closed source. So I felt compelled to put a fair bit of . . . → Read More: FDMDV Modem Page

Testing a FDMDV Modem

By david, on May 1st, 2012

A key use for Codec 2 is digital voice over HF and VHF radio. A few months ago I figured we needed to get Codec 2 on the air. With a PC, codec and modem software, two sounds cards, and a Single Sideband (SSB) radio it is possible to send and receive Digital Voice (DV) . . . → Read More: Testing a FDMDV Modem

Intermittent EV

By david, on February 29th, 2012

A few months ago I was cruising along and my EV suddenly lost power. It was like someone had pushed in the clutch. I lifted the bonnet but the problem seemed to have gone and off I went again. Then it happened again last week. I suspected the throttle pot, as I . . . → Read More: Intermittent EV

Busting Teenage Partying with a Fluksometer

By david, on February 7th, 2012

On New Years Eve 2011 I was in Geelong at a restaurant, 800km from my home in Adelaide. This year I happened to be away from my children, who were staying elsewhere in Adelaide while I was interstate. My home was supposedly vacant. However I knew it was very hot in Adelaide . . . → Read More: Busting Teenage Partying with a Fluksometer

linux.conf.au (LCA) 2012

By david, on January 27th, 2012

Well, it’s that time of year again – my annual geek-week at linux.conf.au. Every day there were many interesting talks to attend and many I had to miss. I am currently catching the ones I missed by watching the LCA 2012 videos.

Keynotes and Open Source DSP

The Bruce Perens keynote had many good points on . . . → Read More: linux.conf.au (LCA) 2012