Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

VCXO as a local oscillator

Status
Not open for further replies.

aloishis89

Junior Member level 2
Joined
Jan 8, 2012
Messages
21
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,447
I need to be able to adjust the local oscillator frequency going into my mixer, but only by a relatively small amount (from about 100 MHz to 200 MHz). I don't want to use a VCO because I can't find any that will go that low, and they're overkill since the ones I've seen give you a range from like 300 MHz to 2.3 GHz. A voltage controlled crystal oscillator has the correct range, however the one I'm looking at is about ±50 ppm accuracy. Is it considered bad practice to use a VCXO as a local oscillator like that? I've only really seen them used before in PLLs.
 

pstuckey

Full Member level 4
Joined
Oct 5, 2011
Messages
220
Helped
84
Reputation
168
Reaction score
83
Trophy points
1,308
Location
Virginia, USA
Activity points
2,486
What is the part# of the VCXO you are looking at?

VCXOs typically have very narrow tuning ranges. Are you sure the +-50 ppm isn't the tuning range?
 

pstuckey

Full Member level 4
Joined
Oct 5, 2011
Messages
220
Helped
84
Reputation
168
Reaction score
83
Trophy points
1,308
Location
Virginia, USA
Activity points
2,486

This family of parts covers that frequency range, but each individual part must be specified for just one center frequency. Then they can be tuned +-50 ppm around that one frequency. So for a 100 MHz VCXO, the tuning range is +-5 kHz.

I've attached is a datasheet of a VCO that tunes over 100-200 MHz, see if this will meet your needs.
 

Attachments

  • RFMD UMS-200-R16-G.pdf
    254.5 KB · Views: 5

aloishis89

Junior Member level 2
Joined
Jan 8, 2012
Messages
21
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,447
Oh ok, I get it. Thanks for recommending that part, that should work great!
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top