# Reference Input clock problem: Connected with Agilent Equipment

**URL:** <https://discourse.myriadrf.org/t/reference-input-clock-problem-connected-with-agilent-equipment/72>\
**Category:** Reference Development Kit\
**Created:** [22 January 2014 08:55 UTC](https://discourse.myriadrf.org/t/reference-input-clock-problem-connected-with-agilent-equipment/72 "2014-01-22T08:55:04Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![lex\_kaka](https://avatars.discourse-cdn.com/v4/letter/l/df705f/32.png) [@lex\_kaka](https://discourse.myriadrf.org/u/lex_kaka)\
**Post date:** [22 January 2014 08:55 UTC](https://discourse.myriadrf.org/t/reference-input-clock-problem-connected-with-agilent-equipment/72/1 "2014-01-22T08:55:04Z")

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The ref input clock is 23~41MHz on board, but measurement equipment REF clock is 10MHz, I want to design a REF clock transform board, the function is 10MHz input, and any frequency between 23M~41MHz output. Does anyone has recommended chips?

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**Author:** ![andrewhux](https://avatars.discourse-cdn.com/v4/letter/a/d07c76/32.png) [@andrewhux](https://discourse.myriadrf.org/u/andrewhux)\
**Post date:** [22 January 2014 14:30 UTC](https://discourse.myriadrf.org/t/reference-input-clock-problem-connected-with-agilent-equipment/72/2 "2014-01-22T14:30:00Z")

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Hi Lex,

Myriad board requires 23-43MHz reference clock as a reference for transmitter and receiver PLL. Usually the clock source for PLL is supplied from clean crystal oscillator such us this:

[http://www.rakon.com/products/families/download/file?fid=39.225](http://www.rakon.com/products/families/download/file?fid=39.225)

Test equipments are supplying 10 MHz for the boards to eliminate frequency error. Such circuitry already is implemented in Zipper board. See schematic, page 9:

> **[myriadrf/reference-development-kit](https://github.com/myriadrf/reference-development-kit/tree/master/zipper/hardware/v2/PDF)**
>
> The Myriad-RF Reference Hardware design files and firmware - myriadrf/reference-development-kit

Andrew

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**Author:** ![lex\_kaka](https://avatars.discourse-cdn.com/v4/letter/l/df705f/32.png) [@lex\_kaka](https://discourse.myriadrf.org/u/lex_kaka)\
**Post date:** [22 January 2014 14:42 UTC](https://discourse.myriadrf.org/t/reference-input-clock-problem-connected-with-agilent-equipment/72/3 "2014-01-22T14:42:49Z")

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Thanks andrew, That is very helpful to me.  
and I have a further question, when hardware is determined, and the 10MHz reference clock is input, Whether the clock in zipper can output any frequency among 23MHz~41MHz(changed by program) or a fixed frequency?

Thank you for your reply.  
Lex

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**Author:** ![andrewhux](https://avatars.discourse-cdn.com/v4/letter/a/d07c76/32.png) [@andrewhux](https://discourse.myriadrf.org/u/andrewhux)\
**Post date:** [22 January 2014 15:19 UTC](https://discourse.myriadrf.org/t/reference-input-clock-problem-connected-with-agilent-equipment/72/4 "2014-01-22T15:19:06Z")

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Lex,

Yes it can. There is a 30.72 MHz crystal oscillator on the board which supplies reference frequency for the Myriad RF board and Clock generator which can generate any frequency (up to 80 MHz) for digital interface. Check page 5 in the schematic.

Andrew.

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**Author:** ![lex\_kaka](https://avatars.discourse-cdn.com/v4/letter/l/df705f/32.png) [@lex\_kaka](https://discourse.myriadrf.org/u/lex_kaka)\
**Post date:** [22 January 2014 19:33 UTC](https://discourse.myriadrf.org/t/reference-input-clock-problem-connected-with-agilent-equipment/72/5 "2014-01-22T19:33:01Z")

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Hi andrew,  
OK, I understood.  
Thank you for your reply.

Lex