SD (software-defined) radio receivers use a bare minimum of hardware, relying instead on their software capabilities. This SDR project demonstrates what’s achievable, in this case a multi-purpose receiver covering all bands from 150 kHz to 30 MHz. It’s been optimised for receiving DRM and AM broadcasts but is also suitable for listening in to the world of amateur transmissions.

www.nti-online.de/diraboxsdr.htm
www.sdradio.org
sourceforge.net/projects/drm
www.g8jcf.dyndns.org

• OpenBTS is a software-based GSM access point, allowing standard GSM-compatible mobile phones to make telephone calls without using existing telecommunication providers' networks. OpenBTS is notable for being the first free software implementation of the industry-standard GSM protocol stack.
• The GSM Software Project: We want to bring together all the folks that are interested in building a gsm receiver.

• via http://docs.google.com/View?id=ddjmqgw3_43gm6gvggf
• http://www.google.com/#hl=en&source=hp&q=pid+kalman&aq=f&aqi=&oq=&fp=7d15299a959dbb33

Roll Rate

File: In sw/airborne/fw_h_ctl.c we define the roll rate loop:

float cmd = throttle_dep_pgain * ( err + h_ctl_roll_rate_igain * roll_rate_sum_err / H_CTL_ROLL_RATE_SUM_NB_SAMPLES + h_ctl_roll_rate_dgain * d_err);

Note that the roll Pgain is variable with throttle and multiplies through the entire equation affecting the I and D terms as well for ease of tuning.

• This demo is a BASIC program that draws a circle and then a sine funtion.
• Library - There are also game and miscellaneous other programs
• http://tinyurl.com/demozx81
• http://www.vavasour.ca/jeff/ts1000/index.html

http://www.qsl.net/py4zbz/DSP/softw.htm "My first SDR is a software demodulator SSB (USB and LSB) with AGC, to be used in conjunction with a hardware SDR such as SDRZero. The I and Q signals produced by SDRZero are applied at the entrance of the stereo sound card, I being in the right channel and Q in the left. Comentarei, com ilustra ões feitas com o próprio BasicDSP, o programa exemplo. Comment, with ilustraões made with the very BasicDSP the program example."

via review for Marantz SA-1152 review http://www.google.com/search?complete=1&hl=en&q=marantz+sa-11s2+sm5866a5&btnG=Google+Search&aq=f&oq=

"attempts to explain the process of MP3 compression in simple terms, without oversimplifying it. Although some parts have been omitted, like the details of stereo encoding schemes and in-depth file composition, it covers the basic theory of turning uncompressed sound files into compressed MP3. In order to tour the MP3 codec without getting overwhelmed by the technical minutiae, we'll take a look at some of the background principles and legacy of MP3, then break the process down into analysis and compression before finally considering the impact that this humble format has had on digital audio. Hear, hear"

How jpg compression works