Beginners DSP eval project  - Page 1
Forum section: electronics / general

author: W7NGA
author_rank: Regular Contributor
timestamp: January 29, 2014, 03:06:13 pm
content: Greetings from San Juan Island, Washington State USA! I am a retired engineer and find myself intrigued with learning to design some simple filters and other projects using DSP. I was hoping to find a low-cost entry level evaluation board to initiate myself to the world of DSP without great expense. As a mathematician I am quite interested in the array math and vector operations and would like to be able to have low-level access to those functions. Just goofing really and nothing serious .. simple filter designing and investigation. I would like to have a USB interface to my iMac, with the support tools running in OSX but if that isn't practical I can find a Windows PC. I have searched the archives without success so I was hoping for ideas. The Analog Devices boards are rather expensive, so I'm thinking TI might be a good alternative. Ideally, I would like enough documentation to lead me through the design process, with the underlying theory, and I am well-versed in the C language and Assembly language.Having worked for Tektronix and spin-offs for twenty years, I thought you might like to see just a few of the scopes in my collection.Daniel

author: nctnico
author_rank: Super Contributor
timestamp: January 29, 2014, 05:25:00 pm
content: Where do the signals you want to process come from? If they are generated then you can just as well use your computer. I prototype all my digital signal processing projects/algorithms on a PC. Much easier than messing around with development boards. You can also use a smartphone or tablet with Android or iOS as a DSP platform. It has an analog input and output... One of my more recent DSP projects runs on an iPhone (with the input high pass filter disabled)!

author: wiss
author_rank: Frequent Contributor
timestamp: January 29, 2014, 07:46:51 pm
content: TI's LAUNCHXL with a tms320F28027 is some 20 eur, only 12 bit adc and pwm out...

author: Rory
author_rank: Frequent Contributor
timestamp: January 29, 2014, 08:41:06 pm
content: Hi Daniel,I've been playing with DSP for several years. Started off with Motorola DSP56K hardware, now obsolete.I would recommend the Smith book,http://www.dspguide.com/if you haven't already read it.I agree with Nico, if you're just into learning the algorithms you can do a lot with a desktop PC. The hardest part is the sound card I/O. I adapted some of the dspguide examples to Powerbasic 8 - FFT and some of the filters - and spent more time fighting the Microsoft streaming I/O API than anything else. There were some articles in QST and QEX a while back regarding Winradio, that explains some of the problems with PC hardware for DSP, and how you can work around them. The examples were in VB6 I believe.Currently working with dsPIC33 architecture, it's cheap and the development tools are free. MPLAB haters, please don't flame. Microchip also has Filterlab for download that does the hard work of generating coefficients. Doing a big project for work right now can't say much about due NDA but we're finding that once you know the kinks inherent in the dsPIC family they're easy to work with. I'm fortunate to have a good friend who's a PIC and DSP guru and he has a huge library of routines he's built over the years that he shares with me.If you're interested in dedicated FIR filters, Quickfilter Technologies has an interesting little QFP package that you talk to with SPI and filters data out at the rate you clock it in. Chip is cheap and easy to use but the evaluation package is somewhat pricey. Digikey has them.

author: nctnico
author_rank: Super Contributor
timestamp: January 30, 2014, 07:06:06 pm
content: Actually you don't need the soundcard at all. I usually create signals with a waveform editor (Cooledit) and use that for analysis or playback as well.

author: JoeN
author_rank: Frequent Contributor
timestamp: January 30, 2014, 07:43:23 pm
content: Quote from: Rory on January 29, 2014, 08:41:06 pmI know nothing about DSP but it is on my list of things to learn, at least the basics. That book looks like "just the ticket". Thanks for the link!

author: Rory
author_rank: Frequent Contributor
timestamp: January 30, 2014, 08:56:55 pm
content: Quote from: nctnico on January 30, 2014, 07:06:06 pmAbsolutely true... but I have a distinctive feeling that Daniel would rather do DSP on live signals like CW or notching out carriers on SSB. Otherwise it's just an exercise in academic mental masturbation...

author: Sypher
author_rank: Contributor
timestamp: February 01, 2014, 04:28:38 pm
content: I'm currently learning DSP as well. A lot of it can be done with software (Matlab, Labview, Octive, Scilab, Scipy, GNU Radio), a few books, and online video lectures. However, I think the best way to learn it is through Software Defined Radio.Coursra has an online DSP course athttps://www.coursera.org/course/dsp.And I'm sure there are more availble on the web, check MIT OCW, Stanfords SEE and such.As for books, the blue book is great b/c its free:http://www.dspguide.com/Other books I have: Understanding Digital Signal Processing and Software Receiver DesignLook into Software Defined Radio. I'm currently have a Universal Software Radio Peripheral (USRP), and it's amazing. It's not cheep tho (~$700) as it's a university and industry standard. Check out HackRF and other low cost SDR's like rtl-sdr (very low cost receive only). I'm currently using GNU Radio; however, it has a high learning curve and requires a lot of programing knowledge. It's extremely powerful tho if you have any software background. Matlab/Octave might be an easier start for EE's.Trust me, one day with an SDR and some DSP software has taught me so much more sitting though university lectures. Being able to visualize an FFT, convolution, or just a filter in action is awesome.