Being an old timer, I'd be tempted to mix down to 455 kHz, filter, and mix back up. ;)
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
THS3201 ...Jim Thompson
--
| James E.Thompson | mens |
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| 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.
I find,
Tim
-- Seven Transistor Labs Electrical Engineering Consultation Website:
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
Or 200kHz, to ease the requirements on the coils even more at the expense of worrying about images. (There were a number of amateur and military radios in the 1950's that would convert down to 455, then again down to
50kHz or thereabouts. It's pretty easy to make a bazzilion-resonator filter, even for code reception, when your IF is 50kHz).Collins Radio used to make an impressive array of mechanical filters for
455kHz. I'm sure that Jim's needs would be addressed quite well by some super-zoot IF filter designed for the AM band. I just don't know if they're available in current production.-- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Den onsdag den 28. januar 2015 kl. 03.19.19 UTC+1 skrev Tim Williams:
then all you need is eight hands and the patience of a saint to trim it
-Lasse
That's one of our favorite opamps. TI makes nice fast stuff, relatively high voltage.
How are you going to nail those frequencies to ballpark 0.1%?
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
A couple of IQ mixer chips would allow a zero-IF structure. Mix down to baseband, lowpass filter the I and Q, and mix back up. That would be a no-trims design. Stopband attenuation might be a problem, but there are hacks for that.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
I'm not the biggest fan of direct conversion, because all the spurs land right on top of you. With some reasonable IF, you can filter out some of them.
Of course if the phase response is more important than amplitude linearity, the performance of RC lowpasses is pretty attractive. (I use them for noise measurements a lot.)
Cheers
Phil Hobbs
It seems hard to me too. How do you tune such a beast? But I would guess Jim is doing it with opamps, and caps. If the cap ratio tracked with temperature...?
George H.
Bingo! (I guess you'll have to take my word that I didn't read ahead.)
George H.
[snip]
Further head scratching suggests that an injection locked loop may be the easier-to-implement solution. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
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| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| 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.
Are you doing clock recovery? Why not a PLL?
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Disappearing carrier, although I have some ways around that problem, but may or may not work in this situation. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| 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.
Den torsdag den 29. januar 2015 kl. 01.42.34 UTC+1 skrev John Larkin:
if it is just for data recovery and at that low frequency just oversample the data and a simple state machine to extract
-Lasse
Off-the-wall proprietary, so I can't say much. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| 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.
OK, I don't know injection locking (IL)... maybe you (and James A. ?) will share? I guess I see it (IL) as pulling a broader resonance to one side or the other.
George H. (opamps are going to be hard because of GBW variation, I think...)
[snip]
THS3201 ?? ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| 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.
Yup. If JT gets that working in a production circuit I'll send him a bottle of Scotch.
Yeah I saw that before.. 2 GHz. You certainly have more active filter experience than me. My only hard data points are from a 100 kHz, Q = .707, filter I made. It is used to do ~1% noise measurements and I measure it to the ~0.1% level. It's made with a 8MHz GBW opamp and there is some Q-enhancement. I see variations in the Q at the ~0.2% level (A quick survey of the last 10 instruments.) I'm not sure where the variation comes from, but I always wondered about GBW variation in the opmaps. You never see that spec'ed.
George H.
Could you use XOR phase detector and an integrating loop filter? That makes the lock very tolerant of dropouts, but maybe you can't afford a big enough capacitor.
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
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