Hi David, what describe (jump to frequency as you tune a station in) sounds like a little bit of sophisticated radio electronics. It suggests that the unit employs synchronous detection, somtimes ca
But surely, when narrowband filtering is in place - as any narrow band mode will of necessity be doing internally - any wideband non Gaussian or bursty noise when applied to this narrow filter will e
Hi Andy things have changed since then. Real time FFTs were just beginning to be possible but not many had much experience at that time. I remember the cleverest stuff I saw was from a graduate stud
Quite simple. Same number of FETs for given power, you either parallel them in half-bridge, or use singly in H bridge But H-bridge give you four times the impedance, and high Z is always good new
continuing... The gate resistor just has to swamp teh Xc of the gate capacitance in a linear amp, to make it look clean and resistive at the input. So, for example, assume 2000pF Cgs at 475kHz. X
Forget my comments about gate resistors, you said for a non linear (switching) design. I was talking about linear amps As the last post said, small values to damp oscillations if any are needed at a
8000 * 60 = 480000 RPM 'jnt On 21 December 2016 at 12:42, Martin Evans <[email protected]> wrote: Forgive me for asking what may be quite obvious to many - but does this mean that if I s
Absolutely brilliant. The best overall description of FEC I've ever read. Andy G4JNT On 26 December 2016 at 07:35, Paul Nicholson <[email protected]> wrote: I wrote a non-mathematical introductory
Is it any more than a CODEC chip? They use SPI or similar and DSP chips have custom interfaces to make the most of them. So the RPi wit its fast serial interface should cope with most CODECs.
What do you have against ferrite in transformers? So long as you obey the flux equation. V = 4.44 .F.N.A.B and keep B down to below 0.1Tesla ferrite will work brilliantly. Certainly does in
Why not keep it simple, and do it like the Decca transmitters? Forget complicated splitters/combiners with messy deliberate isolation. You are combining identical signals so that sort of design is
Any issues in switching modules in /out ... simply a multi primary transformer ? G, From: [email protected] Andy Talbot Sent: Monday, April 10, 2017 7:49 PM To: rsgb_lf_group@blacksheep.
If your PAs are the push pull type using a transformer, you'll have to keep those, and take their secondary winding to the combiner. Not ideal but not a lot you can do if you use that sort of desig
Oops, that should have read V <= 4.44 .F.N.A.B (V RMS) You want to keep B down below some value where it drives teh core into saturation / non-linearity. But not so many turns that copper los
I don't know why more designs based on them haven't appeared. Other than my half bridge version running from 320V DC from raw rectified mains, all the other high power amps around seem to use the cl
... Any change of the load impedance (R,X) on the secondary side is seen by the PA on the primary side proportionally to the step up ratio. Perhaps because it is not so easy to get hold of those orig
Stefan your idea of saturating the transformer is, I think, flawed. If you reduce mu-r of the core by saturating with DC, the primary winding will have vastly reduced inductance and appear as a n
Hi Andy, Yes yes, i agree, and that's what i don't fully understand yet. Last night i played a bit with the transductor that is laying arround here in a cupboard. It didn't take much time to build u
Is that recorded with antenna direct into soundcard (metaphorically speaking ) ? Or with any frequency translation or processing ? I'll play it to the birds in my garden as they cluster round the f
