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Entry  Tue Apr 26 17:06:37 2011, Mingyuan, Tara, DailyProgress, Creak, start crackling 
    Reply  Thu Apr 28 21:55:25 2011, tara, DailyProgress, Creak, start crackling chopping.pdf
       Reply  Fri Apr 29 18:39:37 2011, tara, DailyProgress, Creak, start crackling 
          Reply  Wed May 11 22:17:35 2011, tara, DailyProgress, Creak, start crackling 1khz.pngf_t_response.png
       Reply  Fri Apr 29 21:23:15 2011, tara, DailyProgress, Creak, start crackling ad734_crackle.pdf
          Reply  Thu May 12 23:18:27 2011, ryan, tara, DailyProgress, Creak, start crackling ad734.png
Message ID: 201     Entry time: Thu May 12 23:18:27 2011     In reply to: 192
Author: ryan, tara 
Type: DailyProgress 
Category: Creak 
Subject: start crackling 

 We tested AD734 on the diagnostic bread board, the result is good.

     We want to square/multiply signals between 10 to 100 Hz, so we use AD734 chip to do the work. The circuit is connected as described here

We try to square the signal. the test signals are sine waves at 10 Hz, 50Hz. The output are nice sine waves, but the gain is high (72dB). The chip rails as the input exceeds 0.5 Vpkpk. We will have to check the signal from the PD in the setup to see if it is higher than 0.5 Vpkpk or not. If so we can change the gain of the chip. Otherwise we can go ahead and use it.

 ad734.png

The spectrum of the output, for 10Hz input, there's a peak at 20Hz output. For 50Hz input, there's a peak at 100Hz. The response is flat between this bandwidth.

 

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