Philip A Covington’s Blog

Here is an update on my mini-itx/SDR project: I have been working out the details of the A/D – D/A board. I have decided to use the TI PCM4202 (24 bit, 192 kHz, stereo) for the RX A/D. For the TX A/D and RX/TX D/A I am going to use the TI TLV320AIC23B CODEC (24 bits, 8-98 kHz, stereo, with integrated mic amp and headphone driver). The PCM4204 will be dedicated to RX only. The TLV320AIC23B will handle the microphone input for TX as well as the IQ output for TX and the audio output for RX (in the stand alone configuration). Both chips have digital audio interfaces (I2S, left, right justified, etc…) so I have the problem of getting that data into the PC via USB2.0. I looked at the Cypress EZ-USB FX2 CY7C68013 microcontroller for this but it cannot handle the transfer on its own. I decided to use a Xilinx FPGA in addition to the EZ USB FX2 for the I2S to parallel conversion (inspired by the USRP and SSRP projects of GnuRadio). The EZ USB FX2 will operate in slave FIFO mode t...

Someone emailed me about my webpage at: http://www.philcovington.com/comp.html to ask if I really believed we are living in a computer simulation. He was referring to the paper by Bostrom titled "Are You Living In A Computer Simulation? ". No, I do not believe we are living in a computer simulation. It is an interesting paper though. I think that Ed Fredkin's Digital Philosophy (http://www.digitalphilosophy.org) is probably closer to what underlies reality.

SoftRock 40 I got Tony Park's SoftRock 40 playing today with Bill KD5TFD's modified PowerSDR console. It is amazing what can be done with such a small board. I want to revive the SharpDSP enabled console for use with the SoftRock 40. I will strip out all of the unneeded controls and functionality in the PowerSDR console to make it specific to the SoftRock 40. This will clear up some screen real estate so I can widen the Panadapter window to show all 48 or 96 kHz of bandwidth at once in the Panadapter. When the PCM2900 codec boards become available I will modify SDRAudio to correct for the sample offset problem in the PCM2900. Website I reorganized my website today. The website notes were archived and links to the various software projects were rearranged to make it easier to find a specific item.

A few people have mentioned in the past about wanting to use a small motherboard like mini-itx or micro-atx to run PowerSDR with the SDR-1000 to make a small self-contained unit possibly using a small LCD panel display. That was one of the things on my project list that I wanted to do also. Now that I have started thinking about it again I decided to try a variant of this idea and have had encouraging success so far just playing around with it. I wanted to try to dedicate a mini-itx board to the DSP, CW keyer, and hardware control of the SDR-1000 using real-time Linux (RTAI http://www.rtai.org/ ). I am trying to see how feasible it is to run the DSP (based on the DttSP code) and hardware control code in hard real time under RTAI. The RTAI patched linux kernel with DSP and hardware control code loads from a compact flash card to make it a diskless system (I have it down to under 16 MB now). I'd also like to come up with a A/D D/A add on board that will use a chip like the Wolfs...

The vCOM driver project is now hosted at: http://developer.berlios.de/projects/n8vbvcomdriver/

It turns out Microsoft offers a free download called Windows Media Encoder that will do screen recording. I have tried it and so far it looks good. It is not as jerky as CamStudio and creates smaller file sizes.

I have been trying out various screen capture software that I hope can be used for software demonstations and tutorials. The first I looked at is Camtasia (http://www.techsmith.com). It is nice for creating software tutorials. Next I looked at Macromedia's Captivate (http://www.macromedia.com/software/robodemo/). It has a lot of avantages and I think I prefer it over Camtasia. Unfortunately it costs about twice what Camtasia costs, but I think it is worth it. I will post a test demo using Captivate to see how it plays with users. It saves files in Shockwave format. I will probably do the software tutorials inside a VMWare Workstation 5 instance. My screen resolution is 1280x1040 so I need to do the demos within a smaller screen area... probably 1024x768 since this is the smallest common size on laptops as well as most desktops. I can also undo changes easily using VMWare's snapshot and cloning features. VMWare Workstation 5 also has a movie recorder mode where you ca...