AnsweredAssumed Answered

variable gain amplifier using ADG1206

Question asked by jungaenang on Aug 17, 2015
Latest reply on Sep 11, 2015 by jungaenang

Dear sir

I need help from multiplexer expert. the using ADG1206 which is appled to sonar system have some problems.

the time variable gain amplifier(we called TVG) is consist of mux, non inverting amplifier and band pass filter.

the problem is the transistion voltage from switch turn on / off. I think the problem source are charge injection and offset variations.

simple circuitry is this figure.

그림1.jpg

when input common(noise input maybe), surge voltage appear ADG1206. but real problem is BPF output. This signal  is possible to fault detection on sonar sytem.

그림2.png

1. Trigger (2v/div)

2. ADG1206 output / AD8022 Positive input (100mv/div)

3. Amplifier output (100mv/div)

4. Band pass fiter output(500mv/div)

 

그림3.png

 

1. Trigger (2V/div)

2. ADG1206 output (100mV/div)

3. Amplitier output (200mV/div)

4. ADG1206 s5 (100mV/div)

 

 

the result's yellow trigger digital code change 110 to 010.

I guess this surge voltage(glitch impulse) occur switch turn off after Tbbm(break before make time).

 

I wish ADG1206 output surge voltage eliminate for transition state reduction on BPF output.

(using capacitor has limited by ADC conversion)

comment please.

Outcomes