I'll give this a try and report back. I was also thinking of inducing a large burst on the transmit graph and listening in with a burst tagger on the receive side. James Wanga
On Thu, Aug 25, 2022 at 1:34 PM Brian Padalino <bpadal...@gmail.com> wrote: > On Thu, Aug 25, 2022 at 4:19 PM James Wanga <jwa...@gmail.com> wrote: > >> Thanks Brian! >> >> This is a clever solution. My signal is bursty even through the duration >> of the pulse. Is the purpose of the second threshold circuit meant to >> mitigate that by averaging over time? >> > > Yes, the second signal will rise slowly, and decay slowly (think like RC > time constant) so if multiple back-to-back bursts come in, or there is a > slight fade in the signal, the same burst is kept. It should also give you > a little extra "tail" so that you aren't cutting things off immediately. > > Also note the delay in the beginning that tries to center up the energy a > little bit so you see some beginning noise levels. > > In the end, I get files that should look like what you have, though I did > have to play with gains and threshold levels to make it reliable. > > Let me know if you have success with this. > > Thanks, > Brian > > >> >> On Thu, Aug 25, 2022 at 11:34 AM Brian Padalino <bpadal...@gmail.com> >> wrote: >> >>> On Thu, Aug 25, 2022 at 1:55 PM James Wanga <jwa...@gmail.com> wrote: >>> >>>> I'm receiving a phase modulated signal representing a periodic pulsed >>>> byte that looks something like this: >>>> >>>> >>>> -------------|-|||--||-------------|||--||||-------------|--||||-|------------- >>>> >>>> I'm trying to understand how I might split this signal roughly halfway >>>> between each pulse of activity so I can save each pulse as a separate IQ >>>> fil, bit like this: >>>> >>>> ------|-|||--||------ >>>> >>>> -------|||--||||------- >>>> >>>> ------|--||||-|------ >>>> >>>> The split does not have to be precise, it only needs to avoid bisecting >>>> any of the pulses. Here are some things I've tried.- Creating a custom >>>> block on the receiver that uses a timing interval. Unfortunately, the >>>> pulses aren't perfectly periodic so eventually this causes the split to >>>> drift. >>>> >>>> - Since I also control the transmitter, I tried sending an async pmt >>>> message from the transmitter to the receiver, but again, since the message >>>> is async the timing is too unpredictable to make an accurate enough cut. >>>> >>>> - I was also wondering if there is any way to propagate a tag from a >>>> transmitter to a receiver if both are in the same flow graph, but I >>>> couldn't find any info on how to do this. >>>> >>>> Any Ideas? Thanks! >>>> >>> >>> I was looking at a bursty signal in the ISM band that I wanted to save >>> and came up with the attached flowgraph. The key is the "Burst Tagger" >>> block and the creation of the trigger utilizing the magnitude of the >>> incoming signal. I utilize two "Threshold" blocks - one on the magnitude >>> itself which should rise pretty quickly, and one based on a filtered >>> version of the magnitude which falls slower. Both of those are OR'd >>> together to create the trigger and saved with the "Tagged File Sink". >>> >>> GRC and PDF screen capture both attached. >>> >>> Hope this helps. >>> >>> Brian >>> >>> >> -- >> James Wanga >> >
