viewtouch VS gnuradio

Created a long time ago by a really cool Redditor: https://www.viewtouch.com/

I am a software development manager. I have purchased and awarded every software developer whom I didn't fire after a week or two with a complete set of the books authored and typeset by W. Richard Stevens. My code, GPL'd nearly ten years ago, represents my life's work and is replete with the code found in Rich Stevens' books. I am very proud that I was able to help the programmers I hired to be better programmers and to help them write better code because they were able to rely upon what Rich Stevens was able to pass on to them.

And why are they not running [Point of Sale on Raspberry Pi](https://www.viewtouch.com) ?

Chipsee makes an [all in one 15.6 display](http://www.viewtouch.com/) which will do this much more easily, much more attractively and at less cost than this.

Per his website it would appear he did, as "ViewTouch provides 24/7 phone support and training, updates and backup." So, you know, good, but why not just mention "Yeah I'm doing this through my company that does in fact provide support" rather than "I've been doing this for 35 years"? What am I meant to take from that other than "My software doesn't go down" which sends the message that he's not planning for failure. The worst part of this, then, is that that's not actually the case and this was an opportunity for him to advertise his business rather than just dribbling his highly-experienced balls in the guy's mouth.

I didn't realize the code was GPL but just found it at https://github.com/ViewTouch/viewtouch, which has lots of information. Awesome!

The source code is available via https://github.com/ViewTouch/viewtouch

ViewTouch point of sale offers the use of the software at no cost but does charge $49 a month for 24/7 support.

In gr-dtv transmitter examples for Gnuradio, I see some times people use a resampler block before the RF hardware sink. Say our sampling rate is ~9.14Msps which satisfies the Nyquist criterion because our samples are complex numbers.

2.1. Thanks for that tip, I forgot that I was able to check the source code of the WBFM Receive block. As you have said, there are mostly the same. There are some differences between how values are picked. The WBFM Receive block would be a synonym of Quadrature demod => Fir Filter (decimation => Low pass filter) => FM Deemphasis. 2.3. My question there is why 10 and not 20 or 100. I understand that the idea is to reduce the sample rate asap, but what I don't understand is why those values were picked and how can I understand what would be the "correct" or "best" value. 2.4. I'm not fully understanding what you said. If I check the WB FM recieve source code the values that are supplied as the cutoff freq and transition width of the Low pass filter differ from the one of the example. The webfm would apply a sample rate / decimation / 2 - sample rate / decimation / 32 as a cutoff freq and a sample rate / decimation / 32 as a transition transition width. Calculating those values would end up in different that the ones supplied in this second example. Again, is there a rule of thumb to pick these values?.

Gaussian filter is used only on the tx side, so specifying bt in the receiver makes no sense. Take a look at gfsk mod/demod blocks implementation: https://github.com/gnuradio/gnuradio/blob/master/gr-digital/python/digital/gfsk.py

GNU Radio

Here's the filter coefficients used for the GNU-Radio interpolator block to get you started. This is a 7th order interpolator (i.e., 8 FIR taps) with very good performance. Each "row" of the array sets the delay in steps of sample_time / 128.

From their README: “open-source software development toolkit that provides signal processing blocks to implement software radios.” https://github.com/gnuradio/gnuradio