Tel :

+44 118 979 1238

Fax :

+44 118 979 1283

email :

info@actcrystals.com

Spread Spectrum principle (continued from page 2)

EMI Reduction Data

Main mode: EMI reduction:

Total spread % x frequency (fo)

3rd Harmonic: EMI reduction:

5th Harmonic: EMI reduction:

In line with our ongoing policy of product evolvement and improvement, the above specification is subject to change without notice.

For quotations or further information please contact us at:

3 The Business Centre, Molly Millars Lane, Wokingham, Berks, RG41 2EY, UK

http://www.actcrystals.com

Issue:5 M6

Date:01/02/06

ISO9001: 2000 Registered

Down Spread

Centre Spread

99.000000

100.000000

-30000ppm

+5000ppm

0%

-0.25%

-1.5%

+1.5%

0%

0ppm

-15000ppm

+15.000ppm

Instantaneous Frequencies (100MHz Nominal Frequency)

Note. Tri State not available with 0.5% versions.

1%

0.5%

-1.0%

+0.25%

Total Spread %

Min

Max

Min

-3.0%

-0.5%

-5000ppm

97.000000

100.000000

98.500000

0ppm

101.500000

Spread Spectrum Clock (SSC), the mode energy of a spread spectrum clock is spread over a wider

bandwidth, resulting from the frequency modulation technique. The modulation carrier frequency is in

the KHz range which makes the modulation process transparent to the oscillator frequency. The

controlled modulation process can be on all of one side of the nominal frequency (DOWN SPREAD)

or equally spread either side of the nominal frequency (CENTRE SPREAD) . If OVER-CLOCKING is

a problem to the system then the down spread is preferred.

ACT9200SSC

-1.0%

+0.5%

-10000ppm

Down Range

Up Range

100.500000

99.500000

Down Range

0%

Up Range

Max

+2500ppm

99.500000

100.000000

99.750000

100.250000

-5000ppm

0ppm

-2500ppm

10Log

(

0.12

)

()

Total spread % x frequency(fo)x3

0.12

dB

dB

dB

3%

10Log

()

Total spread % x frequency(fo)x5

0.12

10Log

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