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Choosing the right frequency dividers for pulsatile inputs at 80 and 160 MHz

Question asked by liorg on Apr 4, 2017
Latest reply on May 4, 2017 by MRichardson

Greetings,

 

I have two pulsatile signals whose frequency I wish to divide:

 

A. 8x frequency division of a pulsatile 80 MHz input. As exemplified in the following oscilloscope screenshots, its waveform is somewhat irregular, with a primary ~3 dBm peak followed by a secondary peak that can be up to -4.5 dBm high, in its average power (all measured to 50 ohm load):

 

80 MHz pulsatile input signal - primary peak

80 MHz pulse - secondary peak

 

B. 16x frequency division of a pulsatile 160 MHz input. As exemplified in the following oscilloscope screenshot, its waveform is clean but rather weak (-19.8 dBm in its average power to 50 ohm load, if I've calculated correctly):

 

160 MHz pulsatile input signal

 

In both cases, the optimal output would be a ~10 MHz sinusoidal, or clipped-sinusoidal wave, at ~3.3 Vpp to a DC-blocked 50 ohm load. Other periodic ~10 MHz output signals may also be acceptable, if they satisfy VOH of at-least 2 Volts and VOL of at-most 0.4 Volts, to a DC-blocked 50 ohm load.

 

I've browsed through the wide selection of available prescalers, but seemingly at these frequencies they all expect a strong square-wave input, and output a weak square wave. Can you please suggest which evaluation board of yours, or a cascade of evaluation boards, is most likely to be able to pick up these signals correctly and produce the required output?

 

 

Many thanks,

Lior

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