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HMC833 Frequency Change

Question asked by Komugi on Apr 27, 2016
Latest reply on Apr 29, 2016 by Komugi

Hi,

 

I am using HMC833 as a local signal in a digital
demodulator circuit.

Please refer to the attached file which
shows a simple block diagram.

A single tone signal at 1315.075 MHz is fed
to RF input for test purpose and the baseband signal is monitored.

It also includes 2 screen shots which show the
baseband signal waveform when local frequency is increased by 10Hz.

I need smooth change of waveform in paticular environment. However,
unexpected waveform is seen for

approximately 250usec,which means around 64
symbols would be lost since the symbol

rate in this system is 256kbps. (Some of
them could be recovered by error correction)

 

My question is,

Is this phenomena unavoidable?

Is there any way for reducing the duration
of the unexpected signal?

 

The way of frequency change is as follows.

 

Autocal on

Set the local frequency 1315.075000MHz (both
Int data and fractional data are sent)

Autocal off

Set the local frequency 1315.075010MHz (only
fractional data is sent)

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