Wavelength Dependency in RF Propagation?

Started by Randy Yates in comp.dsp4 months ago 11 replies

In an article in a recent issue of Microwaves & RF magazine, Jack Browne makes the following statement: Frequency plays a part in any link...

In an article in a recent issue of Microwaves & RF magazine, Jack Browne makes the following statement: Frequency plays a part in any link budget, especially for longer links, since long-distance links require the LONGER PROPAGATION DISTANCES of larger-wave-length, lower-frequency signals rather than smaller-wavelength, higher-frequency signals. (emphasis mine). I was miffed ...


Digital Control Applications with the TMS320 Family

Started by Kevin Bowling in comp.dsp5 months ago 1 reply

Does anyone have a hardcopy of this book they'd be willing to part with?...

Does anyone have a hardcopy of this book they'd be willing to part with? http://www.bitsavers.org/components/ti/TMS320xx/1991_TI_Digital_Control_Applications_with_the_TM S320_Family.pdf Regards, Kevin


tools for processing radio-signals

Started by kristoff in comp.dsp8 months ago

Hi all, I do not know if this newsgroup is still alive. I would like to learn to do "offline" signal-processing on radio-signals. E.g....

Hi all, I do not know if this newsgroup is still alive. I would like to learn to do "offline" signal-processing on radio-signals. E.g. consider that I have a wav-file or an iq-file that contains a recording of POCSAG (paging) message. What tools r python libraries can I use to exact the POCSAG message from it? I know there are python packages like scipy and numpy which would he...


Distributed PDM decimating filter

Started by Piotr Wyderski in comp.dsp9 months ago

Hi, If I use a typical I2S MEMS microphone (CMM-4030D-261-I2S for reference), the sample width is 24 bits per the datasheet. At, say, 44100...

Hi, If I use a typical I2S MEMS microphone (CMM-4030D-261-I2S for reference), the sample width is 24 bits per the datasheet. At, say, 44100 samples/second, the required digital I2S bandwidth would then be 24*44.1e3=~1.06Mbit/s. On the other hand, the PDM variant (say, CMM-4030DB-26354) requires clock frequency between 1 and 3.2MHz, with the 2.4MHz recommended value. That gives 2.4Mbit...


Current ASICs

Started by Kevin Bowling in comp.dsp9 months ago 1 reply

Is there still a large market for dedicated DSP ASICs or is that being split into things like ARM chips and Nvidia chips now?

Is there still a large market for dedicated DSP ASICs or is that being split into things like ARM chips and Nvidia chips now?


Recovering one irregular signal in the presence of another stronger one--_in utero_ pulse ox

Started by Phil Hobbs in comp.dsp1 year ago 3 replies

(I posted this in comp.dsp a couple of weeks ago, but most of the actual DSP people seem to have disappeared, so the discussion petered out...

(I posted this in comp.dsp a couple of weeks ago, but most of the actual DSP people seem to have disappeared, so the discussion petered out fairly fast. Trying again here.) Hi, all, Hoping there are still some DSP folks round here despite the evil Google ban. (But I repeat myself.) I'm working on a completely noninvasive sensor for fetal blood oxygen, using optical sensing throug...


Recovering one irregular signal in the presence of another stronger one--*in utero* pulse ox

Started by Phil Hobbs in comp.dsp1 year ago 6 replies

Hi, all, Hoping there are still some DSP folks round here despite the evil Google ban. (But I repeat myself.) I'm working on a completely...

Hi, all, Hoping there are still some DSP folks round here despite the evil Google ban. (But I repeat myself.) I'm working on a completely noninvasive sensor for fetal blood oxygen, using optical sensing through the mom's abdomen. It's a very low SNR measurement on account of all the attenuation. The mom's heartbeat modulates her pulse-ox signal, which is much stronger than the fe...


Variance of white noise

Started by Tom Killwhang in comp.dsp2 years ago 5 replies

I was reading Box and Jenkins Time series analysis and noticed that when they calculated power spectrum they had a factor 2 in the numerator -...

I was reading Box and Jenkins Time series analysis and noticed that when they calculated power spectrum they had a factor 2 in the numerator - see http://www.ru.ac.bd/stat/wp-content/uploads/sites/25/2019/03/504_05_Box_Time-Series-Analysis-Forecasting-and-Control-2015.pdf equation (3.1.12). I couldn't figure out where the 2 is coming from but then I wondered if they define noise a


BCH Encoding/Decoding

Started by Randy Yates in comp.dsp2 years ago 1 reply

I've notieced that in order to decode a page of in-band data, the linux kernel code first computes the out-of-band ECC bytes on the...

I've notieced that in order to decode a page of in-band data, the linux kernel code first computes the out-of-band ECC bytes on the given in-band data (calc_ecc). It is also passed the received oob data recv_ecc. If (byte-by-byte) the calc_ecc does not match the recv_data, then the page is decoded. Why not compute the decoded ECC and compute the locator vector/polynomial right off? Ar...


delta-sigma ADC in FPGA

Started by Rick C in comp.dsp2 years ago 11 replies

Usually when I ask about delta-sigma ADCs in FPGAs the comments are along t= he lines of "terrible idea", "can't mix analog and digital", etc. ...

Usually when I ask about delta-sigma ADCs in FPGAs the comments are along t= he lines of "terrible idea", "can't mix analog and digital", etc. I'm very= much not convinced. =20 I think people have a view of the ADC as being a device with very balanced = specs, resolution, SNR, etc. In this application we need significantly mor= e resolution than we do accuracy. The measurement is differ...


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