Results 1 to 8 of 8
  1. #1

    Default How does self-calibration work?

    When you see a radar detector capable of "self-calibration," what exactly does this mean? I am looking for a technical explanation if anyone has one.

    Thanks

  2. #2
    Advanced Member
    Join Date
    Dec 2004
    Location
    Michigan
    Posts
    7,509

    Default Re: How does self-calibration work?

    Quote Originally Posted by parasonic
    When you see a radar detector capable of "self-calibration," what exactly does this mean? I am looking for a technical explanation if anyone has one.

    Thanks
    In the case of the Belscorts, the 2nd LO is crystal referenced, so it is pretty accurate. The detector sets the 1st and 2nd LOs to specific values, and then looks for (normally unwanted) mixer products which occur from mixing the 1st and 2nd LOs. By looking at these "markers" the 1st LO can be adjusted or "calibrated" with pretty good accuracy.

    In a detector that self-calibrates in this manner, there is less of a need to "oversweep" to ensure that the police bands are covered when the detector's oscillator drifts around. Less extra sweeping results in a sensitivity gain.

    Jim

  3. #3

    Default

    What are the frequencies of the LO's, and what IF's do you get, typically? Also, what would the frequency be for the sweep/scan? (This is really helpful to my understanding!)

  4. #4

    Default

    Anyone?

  5. #5
    Advanced Member
    Join Date
    Dec 2004
    Location
    Michigan
    Posts
    7,509

    Default

    Typically:

    1st LO = Can sweep from 14.5 GHz to 15.5 GHz
    2nd LO = Can sweep from 3.994 GHz to 4.194 GHz

    1st IFs = 3.188 GHz, 5.0 GHz
    2nd IF = 906 MHz

    In the case of self-calibration, the second mixer is bypassed and the 2nd IF of 906 MHz is output directly from the 1st mixer (in which case it is actually the first IF).

    To calibrate, the 2nd LO is set to 4.025 GHz, producing a 4th harmonic at 16.1 GHz. The 1st LO is swept until there is an IF signal at 906 MHz. Then, the micro knows that the frequency of the 1st LO is at 15.194 GHz (16.1-15.094=.906) and the VCO voltage reference for that frequency, at which point it is calibrated.

  6. #6

    Default

    How did you get so much learnin's, man?

  7. #7
    Professional
    Join Date
    Sep 2006
    Location
    Toronto, On
    Posts
    1,108

    Default

    I'm so lost..............

  8. #8
    Radar Fanatic
    Join Date
    Nov 2005
    Posts
    1,534

    Default

    Makes sence, Jim. But like TRC, i'm still confused some what as well :?
    RR

 

 

Similar Threads

  1. Replies: 3
    Last Post: 09-28-2010, 06:44 PM
  2. Self calibration - how often?
    By justin81 in forum Escort
    Replies: 13
    Last Post: 01-09-2008, 05:33 PM
  3. self calibration??
    By stamp4 in forum Beltronics
    Replies: 7
    Last Post: 11-18-2007, 01:08 PM
  4. x-50 Self Calibration
    By jtslmn720 in forum Escort
    Replies: 6
    Last Post: 09-18-2006, 07:51 PM
  5. calibration
    By SCjohn in forum Radar Detectors - General
    Replies: 6
    Last Post: 08-16-2005, 04:03 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •