FM PLL Demodulation

particular receiver hardware. It probably WILL turn out to be a custom-designed software receiver. But I'm just at the concept stage now. I just want to get the best possible threshold performance for detecting the 19 kHz tone in faded conditions.

will be limited to the rather high noise floor there which increases 10 dB/dB at threshold. That will be my limit of weak signal performance.

directly at RF, taking advantage of the fact that its spectral components will be easy to distinguish (as a sinusoid) from the random program audio surrounding it. Detecting those spectral components (which are just one pair of Bessell tones due to their low mod index) should be doable in a pre-detection noise BW of a couple hundred Hz or so. I hope.

intuitively it seems valid to me at least.

I can see one way of doing it digitally, but it won't be cheap. Basically you need a "comb" filter. 100 MSPS ADC and FPGA to process its output. Then since you already have the FPGA use it to detect (perhaps even keeping AM or Costas synchronous LF PM intact).

?-)

Oxymoron. Decapitation is strictly physical. It does have mental consequences - the detached head doesn't continue thinking - but anybody using the phrase is proclaiming themselves to be illiterate.

And there's nothing retarded about Phil's emotions - they seem to overwhelm him inordinately rapidly.

Speaking as an Australian, Phil is unusually likely - even for an Australian - to become provoked into insults and profanity. He's not be explained by foreign customs and norms.

"josephkk"

That wasn't even the first IC type. I was seeing them in the early 1970s, RCA IIRC.

Appeared in about 1975.

It used a simple switching matrix to get L and R outputs.

Earlier ones were full of horrible tuned circuits.

.... Phil

Was that 1310 originally from NS ?

I used the Motorola MC1310 in the early 1970's.

The only available PLL alternative was the RCA part (3090) which required IIRC an LC tank at 76 kHz, so without proper test instruments, I used the MC1310.

Bandpass filtering at 19 kHz are quite BIG followed by a frequency doubler and Big filter at 38 kHz, before entering a diode ring demodulator.

Had my first home brew FM tuner going by mid '75 - with varicap front end and a large edge meter for frequency read out.

It may well be that the MC1310 decoder was first.

.... Phil

Yep. I have no problems with his technical content. Just imagine if you were a newbie posting a question that 'offend' Phil - no telling how much damage can he do - perhaps enough to drive a new, unsure hobbyist into another pursuit.

The s*it of it all is that Phil *knows* how much hurt abuse (1) can cause because he has been abused - but rather than being even a *little* bit smart he tries to heap the same pain on others. Well done Phil! And for some reason he wants to be too stupid to learn (ten deep breaths, ask yourself will it matter in 100 years? and then let it go)

(1) I'm not referring to or suggesting anything sexual

And of course while he pretends to be big and brave with no fear of the consequences of his threats and insults, he does it all from behind a fake email address!

How's that for being a hypocrite?

I never meant to suggest that all Australians are like Phil. Think of Phil as a bistatic digital person. He's either on or off, with nothing in between. The rest of us are more linear.

Speaking of Australia, I'm rather irritated with Australia due to past litigation and continuing harassment by the CSIRO against various wireless manufactories. Most recently: which sorta covers both sides of the problem. Rather than initially join the patent pool or consortium, the CSIRO decided to wait until the participants had huge investments in the technology, and then sue. So, I've been boycotting Australian electronics since 2005 when the CSIRO singled out Buffalo Tech as their intended example victim: In effect, it has become an Australian government sponsored war against the wireless industry for profit.

The only problem is that can't seem to find any Australian electronic products to boycott.

Then it couldn't be the first, i used an RCA PLL type in 1973.

I don't remember the original part numbers. The RCA part i used had an rc

?-)

detecting the

Ummm, no. A Costas loop does not decode FM stereo, but entirely other signals. Moreover, by the time the pilot tone is lost the L-R differential component is long gone.

?-)

Well, the scientists involved did invent the technology and then those 'others' with the huge investment ripped it off for their own profit and also falsely tried to claim it as their own invention. Had that happened to a US company/scientist what do you think they would do? Oh, wait TI sued the Japanese electronics industry for patent infringements on the transistor about 30 or so years ago - that was well after the Japanese had invested much more in to electronics industry (proportionally). So put your righteous indignation away. CSIRO has done nothing that an American company hasn't donefirst.

And CSIRO has not been so aggressive as to shut down or make any manufacturer in the wireless industry unprofitable (which they could have) - so those intellectual pirates are all still in the industry and making sufficient money. They just wanted to be making more.

It's a metaphor. It means "as if decapitated, as regards mental capacity". Anyone who doesn't see that is too literal-minded.

Apparently I was not clear enough, I was referring to the post-FM detector signal consisting of 0-15 kHz M (mono) signal (L+R), 19 kHz pilot, the S ("stereo difference") signal (L-R) between 23 and 53 kHz (DSB) with a suppressed carrier at 38 kHz and 60-74 kHz SCA signal (USA) or data broadcast at 57 kHz (3x19 kHz ) in Europe.

The Costas loop would be usable for decoding this S-signal.

With strong signals, the multipath propagation will act just like a comb filter, taking out selectively some point frequencies in the

Thus, it might make more sense to use a Costas loop to decode the S-signal, instead of relying on the 19 kHz pilot, but I have no practical experience, especially about multipath conditions.

Multipath and weak signals are quite different environments, so different approaches are justified.

There is a similar situation with satellite broadcasts. While it is quite easy in analog satellite transmissions to add extra audio-only subcarriers, the reception requires that the whole 27 MHz (or whatever) transponder can be received above threshold and _only_then_, the audio channel can be separated.

Of course, such systems would NOT be useful for mobile audio-only satellite reception.

In this case it was used to mean that his mind has co contact with reality.

Sloman is the oxymoron. Knows EVERYTHING, but too stupid to find any kind of work.

Have you actually read the article in "The Register"? CSIRO wanted a royalty of $4 per device, and eventually got it. This isn't any kind of war - it's standard commercial practice.

There is apparently some niche production going on here - the Cambridge Instruments EBMF 10.5 electron beam microfabricator which we sold to AWA in the mid-1980's is apparently still going strong in some renamed spin-off, selling specialised silicon on sapphire stuff, and hiring semiconductor physicists from time to time.

With a domestic market of just 22 million, and an over-valued currency, it's not an obvious place to set up an electronic production line. For a while we made all the atomic absorbtion spectrometers worth buying, but the CSIRO spin-off responsible - run by the Frew family (who didn't hire me when I applied for a job there) got taken over by Varian.

If you were in the market for a confocal microscope, you could boycott that. The original invention was English, but my mate Martin Harris invented an improvement while out drinking with a mate from CSIRO and everybody who makes confocal microscope these days has been paying royalties to Optiscan and CSIRO.

"Jeff Liebermann"

( ship whole load of paranoid s**te )

There are none so deaf as those who will not hear.

.... Phil

It wasn't any kind of metaphor, just an oxymoronic illiteracy by a guy with a poor grasp of what the word "decapitate" means. Anybody who has been decapitated is entirely mindless, and the added extra "mentally" is utterly redundant.

Really? This is an incidental side-effect of decapitation. but Jim Thompson has been out of touch with reality for years without ever having lost his head. In fact, Phil Allison is thoroughly in touch with reality, or what passes for reality around here, and makes himself obnoxious by describing what he perceives in distinctly unflattering terms. Your claim means that it's you who is out of touch with reality.

Since an oxymoron is a self-contradicting string of words usually just two), and "Sloman" is just one word, I can't possibly be an oxymoron.

If you knew a bit more than you do, you'd know enough to be aware that while I know a great more than you do, there is a much larger universe of stuff that I don't know much about, and have enough sense not to discuss.

And I'm by no means too stupid to find any kind of work - I'm just having trouble finding paying work doing stuff that I'm good at. Since you are just as workless as I am, you'd be equally stupid.