RE: [Discuss-gnuradio] Some noodling

[Marcus Leech]

Turns out I didn't need to write a new block,  but rather through clever
abuse of
  keep_one_in_n(), I was able to implement a cheap "mute and pause".
Which means that
  I can control the two different streams, and control what gets to the
final integrator.

While we're in "switched" mode, I simply pause the main chain, and only
the side-chain
  gets data, and visa versa.  The side-chain data are used to drive a
short-term estimate
  of the reference signal power, which gets subtracted on the main
chain. 

-----Original Message-----
From: Johnathan Corgan [mailto:address@hidden 
Sent: Wednesday, August 20, 2008 12:16 PM
To: Leech, Marcus (CAR:1A12)
Cc: address@hidden
Subject: Re: [Discuss-gnuradio] Some noodling

On Tue, Aug 19, 2008 at 2:00 PM, Marcus Leech <address@hidden> wrote:

> Controlling the switching function is no problem.   But processing the
> samples as they come in has me a bit stumped,
>   unless I write a custom-processing block.

This is your best bet.

> So, the input switches at some rate (a few Hz), which means that the 
> samples sometimes represent the "sky", and  sometimes represent the 
> calibrator.  I can tag the samples so that samples that come in during

> the time when
>   the input is "sky" will be positive, and those that come in during 
> "calibration" will be negative.

It's pretty straightforward to write a new block that only passes
positive samples (or negative, depending on a constructor parameter.)
Then you'd attach two of these to the output of your usrp block and
you'll have the two streams you need.

--
Johnathan Corgan
Corgan Enterprises LLC
http://corganenterprises.com/