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Entry  Sun Jan 30 19:26:03 2011, Koji, Summary, Green Locking, Prototype freq divider freq_divider.pdfIMG_3813.jpgIMG_3814.jpg
    Reply  Wed Feb 2 03:27:20 2011, Koji, Summary, Green Locking, 85MHz Freq divider freq_divider.pdfIMG_3816.JPGIMG_3818.JPG
       Reply  Wed Feb 2 09:56:55 2011, Koji, Summary, Green Locking, Installed the freq divider and Rana's PFD freq_divider_installation.pdf110201_freq_divider_output.pdf
          Reply  Wed Feb 2 10:44:26 2011, Koji, Summary, Green Locking, Freq fluctuation measured by the freq divider and Rana's analog PFD 110201_green_freq_fluctuation.pdf
             Reply  Wed Feb 2 12:55:34 2011, Koji, Summary, Green Locking, Freq fluctuation measured by the freq divider and Rana's analog PFD 
             Reply  Sat Feb 5 23:03:04 2011, rana, koji, Summary, Electronics, Analog Frequency Discriminator: splitter + mixer + long cable mixer.pdfUntitled.pngfsm.png
                Reply  Sun Feb 6 02:29:28 2011, rana, Update, Electronics, Analog MFD: longer cable mfd18.png
Message ID: 4237     Entry time: Wed Feb 2 03:27:20 2011     In reply to: 4228     Reply to this: 4238
Author: Koji 
Type: Summary 
Category: Green Locking 
Subject: 85MHz Freq divider 

The freq divider was built and installed in the beat detection path.

Attachment 1: Circuit diagram

  • Input stage:  Wideband RF amp with DC block at the input and the output. The gain is 10dB typ.
  • 2nd stage: Ultra fast comparator AD9696. Note: AD9696 is an obsolete IC and there are only a few extra at Wilson house.
    The output is TTL/CMOS compatible.
  • 3rd stage: 14bit binary ripple counter (fmax~100MHz.)

Note: I have added 7805/7905 regulators to the circuit as I could not find -5V supply on the 1X1/2 racks.

Attachment 2: Packaging

  • The box is german made Eurocard size box from Techno-Isel Linear Motion http://www.techno-isel.com/lmc/Products/EnclosureProfiles11055.htm
    The box is excellent but I didn't like the fixing bolts as they are self-tapping type. I tapped the thread and used #6-32 screws.
     
  • The prototyping board is BPS's (BusBoard Prototype System http://www.busboard.us/)  SP3UT. The card size is 160mm x 100mm.
    The other side is a ground plane and the small holes on the board are through holes to the ground plane.
    This particular card was not easy to use.
     
  • The input is SMA. Unfortunately, it is not isolated. The output is an isolated BNC.
     
  • The supply voltage of +/-15V is given by the 3pin D-connector. The supply voltages have been obtained from the cross connect of 1X1.

Attachment 3: Input specification

  • The input frequency is 10MHz~85MHz. At lower frequency chattering of the comparator against the multiple zero crossing of the (relatively) slow sinusoidal waves.
  • The input amplitude. There are no apparent degradation of the freq jitter when the input power was larger than -30dBm.

 

Attachment 1: freq_divider.pdf  35 kB  | Hide | Hide all
freq_divider.pdf
Attachment 2: IMG_3816.JPG  322 kB  | Hide | Hide all
IMG_3816.JPG
Attachment 3: IMG_3818.JPG  126 kB  | Hide | Hide all
IMG_3818.JPG
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