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:2 M6

Date:26/10/05

dB

dB

dB

3%

10Log

()

Total spread % x frequency(fo)x5

0.12

)

Total spread % x frequency(fo)x3

0.12

Total Spread %

99.750000

100.250000

-5000ppm

0ppm

-2500ppm

Down Range

0%

+0.5%

-10000ppm

0ppm

10Log

(

0.12

)

10Log

(

ACT9300SSC

-1.0%

-1.0%

0%

-0.25%

+0.25%

+2500ppm

99.500000

Up Range

Min

Max

Down Range

Up Range

Min

Max

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.

97.000000

100.000000

98.500000

101.500000

0ppm

-15000ppm

Instantaneous Frequencies (100MHz Nominal Frequency)

Note. Tri State not available with 0.5% versions.

1%

0.5%

+15.000ppm

-3.0%

100.500000

99.500000

-5000ppm

+5000ppm

100.000000

-0.5%

+1.5%

-30000ppm

0%

Down Spread

Centre Spread

99.000000

100.000000

-1.5%

ISO9001: 2000 Registered

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