The NSA has one of those moveable taps. Whenever someone investigates NSA wire taps, they seem to have moved to somewhere else. I don't use wire or transformer taps because they require a court order to install and I just hate the paperwork.
Hint: It's the night of the full moon and I should be out howling instead of pounding plastic. Snarl...
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Yep. :-)
Eventually I'm looking to construct a micro power radio using phase modulation. It seems a PLL / VCO feedback loop is still the way to go...
On a sunny day (Sat, 22 Jun 2013 22:37:11 -0700) it happened "greysky" wrote in :
You change the FREQUENCY of the local oscillator, and compare phase in a phase comparator. Changing the frequency will change the phase (over as many degrees as you want).
Very simple to change frequency, use a varicap if it is a LC oscillator. Use a 4046 PLL if it is digital.
Also a lot of Sony portable shortwave radios have this feature. It is hard to do a really decent synchronous detector. The Sony radios "growl" at time since getting synch can cause low frequency audio. The Drake R-8 (forget which rev) is a bit better. The AR7030 is very good. I never heard the Sherwood so I can't comment on it.
Sychronous demod or lack thereof isn't a show stopper, but it is useful at times. Mostly if there is a strong interference, you can tune to the sideband furthest away.
Most of the shortwave radio manufacturers left the business. Streaming put them out of business. XM used to have a cool world radio channel. They would switch around from DW, Radio Netherlands, etc. But they dropped the channel. They still have the BBC though.
Getting the BBC on shortwave actually takes some gear these days. They dropped all their North American sites years ago.
Radio Havana is worth a listen.
Well, the usual method would be to use the RC circuit the other way round, and use a varactor. Using a dual allows you to cancel the even order distortion products, like so:
0-----*-----------RRRRR------*---------RRRRR--------*-------0 | | | | | | R | |\ | R *--| \ | R |- \ | R | \ | | | >--------------* | | / | |+ / *-------------------------| / | |/ | V \/ C == A P BB201 | | *------BIGR----0 Vphase | | V C == A /\ P | GNDWith an 8:1 varactor, this gets you a range of about 40 to 140 degrees' phase in a single section, but it's a bit nonlinear due to the varactor's C(V) curve. You can get a nice linear curve with a wider range by using the varactors with an inductor in series and another one in parallel to the series combination, and put the two resonances just outside the range of the varactor. You series-resonate it just off the high-capacitance end, and parallel-resonate it just off the low capacitance end.
0-----*-----------R2R2-------*---------R2R2-----*-------0 | | | | | | R | |\ | 1 *--| \ | R |- \ | 1 | \ | | | >----------* | | / | |+ / *-------------------------| / *----* |/ | | L L 2 1 L L 2 1 | | | | | | | V \/ | C == | A | P BB201 | | | | | *------BIGR----0 Vphase | | | | | V | C == | A /\ | P | | GND GNDYour average hyperabrupt varactor will get you a range of just about the theoretical 0 to 180 degrees, with maximum nonlinearity of about +- 4 degrees, which is pretty good--better than good enough to use inside a feedback loop, provided you don't run out of range. You might need to use a few BB201s in parallel to get enough capacitance for this at 1 MHz.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 USA +1 845 480 2058 hobbs at electrooptical dot net http://electrooptical.net
This one was AM modulation (actually OOK), but AGC (synchronous) and demodulation were done using a PLL...
Admittedly 40 years ago, but basics are basics are basics... >:-}
If I have the time in the next few days, I'll reconstruct that as a block diagram such that functionality can be seen, unobscured by a hard-to-follow device-level schematic ;-) ...Jim Thompson
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| James E.Thompson | mens |
| Analog Innovations | et |
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| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
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I love to cook with wine. Sometimes I even put it in the food.
The principle applies regardless of frequency, although most applications have been in the microwave. In another posting, the OP said that the carrier was nominally 1 MHz, and he's looking for something like one Hertz plus or minus, so we are talking parts per million. The serrodyne literature is large. Google and you will find far too much to ever read.
Joe Gwinn
Today I went to the drive through at one of our local donut shops, when I got to the menu board I noticed the Face Book and Twitter logos. I know they have Wi-FI but I don't remember seeing those logos before.. I asked the window attendant if they had camera's in the place, he said yes. I said oh that's just great, then I asked him if he was aware of facebook and twitter claiming rights to all video recorded? He didn't seem to know about that. Also as you know the FEDs, NSA etc have been using the social networks as a tool for watching people, they don't hide this if you read the fine print when you walk in on these eating places, but most people are to busy thinking about their stomach to read that crap and they know this.
In any case, I told him that I will not be stopping at that location any more. I don't like the world watching me eat nor do I want them to see me driving through the pick up window. When I drove out of the lot I did notice a camera in the window pointing outwards at the main road where they can even capture non-customer cars.
Jamie
They're going to get you >:-} ...Jim Thompson
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| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Even they don't want him. Maynard should move to the land of Oz, so he can be with his brothers Bill & Phil.
Just because they've got FB and Twit logos doesn't mean they're live streaming your mug over the internet from their security cameras.
Those companies probably just want you to tweet about them and "like" them on FB, since "social media" is supposed to be the big thing.
Just about every retail establishment has security cameras- mostly to watch for robberies by outside and inside perps.
Hey, are you affected by all that H2O out there? Looks real bad from what I've seen. 8-(
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
So much for my attempt at humor.
You'll be patronizing fewer such establishments in the future. I've been helping one of my friends with his private security business. Ever since the Boston Marathon bombings, the camera installation part of his business has increased dramatically. He currently has a backlog of installations and at least two new competitors with the same business plan. The cities are doing much the same, but at a slower rate. My recent visit to a local shopping mall found several well hidden new cameras. My office building now has remote monitoring, 4 IP cameras, and 3 more awaiting installation. I have 3 cameras and a DVR in the office that records everyone that goes in and out (thanks to one break in and some opportunistic pilfery).
I suspect that with the increasing prevalence of such surveillance systems, cameras will soon become part of the background scenery, to be ignored and forgotten until needed. You can try to fight them, but I don't believe you will have much success.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
A better response...
Just because you're paranoid doesn't mean they're _not_ out to get you ;-) ...Jim Thompson
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| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
want).
Well, once the local oscillator matches the external frequency, it wont make sense to change that frequency. Once lock occurs, then I want to be able to compare the phase of the two waveforms. Wont a phase comparator work if the the inputs are the same frequency but out of phase by some amount?
want).
PFD ...Jim Thompson
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| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
On a sunny day (Sun, 23 Jun 2013 21:28:46 -0700) it happened Greysky wrote in :
want).
Once lock occurs, phase lock that is, yes then they will have the same phase. But you cannot measure phase unless you get frequency lock first. It does not make sense UNLESS your phase changes constantly, then you can use a phase locked loop and get the phase changes from the error voltage. There is not such thing as 'absolute phase' in the universe.
Phase locked loop example, the error voltage is proportional to the phase CHANGES, how fast changes you can detect is set by the loop filter:
instantaneous phase error output ^ | | signal 1MHz ------>-------- phase comparator ----->----loop filter
------->------ VCO (= voltage controlled oscillator) ---- | | ^ | | |
------- loop filter -->-- VCO (= voltage controlled oscillator) ----->-- phase shifter carrier relative to input | | ^ | | | ---------- phase shifted carrier relative to input
So what do you want to accomplish?
Ahh, Is the frequency known 'in theory' (like it's radio station 970 on the AM dial?) or exactly.. as in you are generating the signal bouncing it around and then detecting it again? (Why does this feel like twenty questions?)
As others have said it sounds like a PLL... But you've gotta get the frequency set before worrying about the phase..
George H.
This all sounds so off-beat. Does the initial poster realize that frequency and phase are related? That the latter is the time integral of the former?
Jeroen Belleman
It isn't necessarily stupid to avoid a PLL. A feedback loop made with a phase-frequency detector and a phase shifter could be the bee's knees for a niche application, because it would avoid the huge low-frequency noise amplification that occurs in oscillators, i.e. you could make it much cheaper for the same jitter performance.
However, one of two things would have to be true: either (a)you know in advance that your total phase excursion will be less than
+- pi radians, or (b) it's okay if the loop loses lock occasionally and re-acquires after skipping a cycle.Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Phil, Can you show us an example schematic? It puzzles me how that could be lower noise than a high-Q (tank) oscillator. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
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