Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Forums Magazine Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Anritsu Alliance Test Equipment Amplifier Solutions Anatech Electronics Axiom Test Equipment Berkeley Nucleonics Bittele Centric RF Conduct RF Copper Mountain Technologies Empower RF everything RF Exodus Advanced Communications Innovative Power Products ISOTEC KR Filters Lotus Systems PCB Directory Rigol RF Superstore San Francisco Circuits Reactel RFCT TotalTemp Technologies Triad RF Systems Windfreak Technologies Withwave LadyBug Technologies Wireless Telecom Group Sponsorship Rates RF Cafe Software Resources Vintage Magazines Thank you for visiting RF Cafe!
Innovative Power Products Couplers

Wideband FM @70MHz? - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2010 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2010, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. Regardless, there are still lots of great posts in the archive that ware worth looking at. Below are the old forum threads, including responses to the original posts.

NOTICE: The original RF Cafe Forum is available again for reading, and the new RF Cafe Blog is an active board.

-- Amateur Radio

-- Anecdotes, Gripes, & Humor

-- Antennas

-- CAE, CAD, & Software

-- Circuits & Components

-- Employment & Interviews

-- Miscellany

-- Swap Shop

-- Systems

-- Test & Measurement

-- Webmaster

Mike_From_Plano

Post subject: Wideband FM @70MHz? Posted: Tue Apr 21, 2009 5:13 pm

Captain

Joined: Mon Apr 20, 2009 2:04 pm

Posts: 14

Hello,

I've been workng on a fiber optic video link and I chose to try 70MHz FM. This used to be fairly easy using components from Signetics; they had a 70MHz IF chip with a built in qud detector and a 150 MHz PLL.

Well, I'm feeling a bit like Rip Van Winkle, I look around and there are all of these phase modulation parts and PLLs that are up in the GHz, but I'm not finding anything quite like I was used to. I'm also on a tight power budget (battery powered...), so I don't think anything the digital folks offer would be of any help.

Anybody have any suggestion for an OLD analog engineer?

Best Regards,

Mike

Top

yendori

Post subject: Re: Wideband FM @70MHz?Posted: Wed Apr 22, 2009 2:28 pm

General

Joined: Thu Sep 25, 2003 1:19 am

Posts: 50

Location: texarcana

Hi Mike,

This is Rod from Plano.

Here are some links you may or may not have already checked.

http://www.freescale.com/

http://www.nxp.com/

http://www.intersil.com/cda/home/

http://www.analog.com/en/index.html

http://www.ti.com/

http://www.national.com/analog

http://www.linxtechnologies.com/

http://sanyo.com/

http://www.digikey.com/

http://www.mouser.com/

Good Luck,

Rod

Top

biff44

Post subject: Re: Wideband FM @70MHz?Posted: Wed Apr 22, 2009 8:56 pm

Colonel

Joined: Wed Apr 08, 2009 11:07 am

Posts: 33

Good luck! I am in a similar situation. I am doing a non-coherent coding gain experiment with fsk receivers, and needed a simple 915 MHz receiver chip with an ANALOG fm demod out. I searched around for hours. Nada. Everything nowadays is too complex, data slicers, no access to the analog output, no access to the ADC outputs, etc. I did finally find a small quantity of old RFM chips on ebay, and am all set. You might find the chip style you are looking for on ebay, especially where the HAMs are selling stuff.

You could probably find a chip if you are willing to go down to either 10.7 or 13 MHz. A lot of wireless keyboards and mice were designed at 13 MHz, so the reciever chips are probably still available. They just recently moved up to bluetooth frequencies.

You could probably find a receiver with some sort of zero IF with an fsk demod output.

Good luck

Rich

_________________

Rich

Maguffin Microwave Consulting

www.MaguffinMicrowave.com

Top

Mike_From_Plano

Post subject: Re: Wideband FM @70MHz?Posted: Thu Apr 23, 2009 1:04 am

Captain

Joined: Mon Apr 20, 2009 2:04 pm

Posts: 14

Thanks guys,

I appreciate your support. It seems we're caught up in the knowledge of the ancients. I'm contemplating going old-school on this thing - complete with messy cans.

Hmmm, I wonder how good the ol' SA602 would be as a quad detector? It has the bandwidth. Then, I need a good IF, complete with limiting.

Anybody have any suggestions for the IF / limiter? I'd hate to go bone knives and bear skins on it...

Mike

Top

biff44

Post subject: Re: Wideband FM @70MHz?Posted: Thu Apr 23, 2009 4:52 pm

Colonel

Joined: Wed Apr 08, 2009 11:07 am

Posts: 33

As long as you are not endeavoring to construct a mnemonic memory, you should do fine.

_________________

Rich

Maguffin Microwave Consulting

www.MaguffinMicrowave.com

Top

biff44

Post subject: Re: Wideband FM @70MHz?Posted: Fri Apr 24, 2009 11:59 am

Colonel

Joined: Wed Apr 08, 2009 11:07 am

Posts: 33

seen on ebay:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0193331528

not sure if that price is for 1 or 10 pcs.

_________________

Rich

Maguffin Microwave Consulting

www.MaguffinMicrowave.com

Top

Mike_From_Plano

Post subject: Re: Wideband FM @70MHz?Posted: Fri Apr 24, 2009 4:10 pm

Captain

Joined: Mon Apr 20, 2009 2:04 pm

Posts: 14

Hey Rich,

Pretty sweet chip, but I gotta move these things into production. I spoke with a fellow at Analog Devices and he suggested the AD603 as an IF. It's good for 90MHz, has an AGC, and high output drive. I think I'll give it a shot with an attenuator (to reduce reflection), and a pair of schottky's for limiting.

That still leaves me looking for a modulator / demodulator that can give me the bandwidth at 70 MHz. I'm tempted, on the demodulator, to run a 1/4 wave delay off of the limiter and beat it against the original. I don't know what it would do for my S/N, since the signal would be small, but it'd sure be simple.

PLLs make my head hurt. Fast PLLs make it hurt worse....

Posted  11/12/2012

withwave microwave devices - RF Cafe
RF Cascade Workbook 2018 by RF Cafe
everythingRF RF & Microwave Parts Database - RF Cafe
Holzworth RF Synthesizers
RF Electronics Shapes, Stencils for Office, Visio by RF Cafe

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free

 

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024

Webmaster:

    Kirt Blattenberger,

    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:

AirplanesAndRockets.com