High resoulustion comparator with dc blocking

Dear all,

I have a signal with a DC voltage  around 2V ( as it's used in receiver side, the DC is determined by power detector output and is varying between 0.2 to 2 V) the freequency is 200kHz-10MHz and the AC voltage is 13-15mV . I want to retrieve the pulse using an ADC. I want to know which ADC (or comparator) can be used? The attachment you can find one example of my signal at the  output of RF front-end. In this example, the  signal at the input  RF front-end is a 200KHz pulse  with 50% duty cycle. The desired output would be  with VH=1.2V and VL=0 V. I tried to use AD8611 with dc bloc cap (1uF)  but It didn't work...

Thanks in advance,

Eleci

Parents
  • Hi,

    I tried your circuit for my design but It didn't work. I prepared the PCB and redesigned for AD8067 and AD8611 but tha output It's not acceptable!!!!

    I also tried to use only AD8611 ( I used an amplifier before comparator  and a HPF to remove DC component) but It didn't work. When I use the DC block, at the input of AD8611, the DC voltage increases at Pin 2 ( I also checked by adding a resistor (330ohm) after DC block capacitor (2.2nF) and ground but nothing changed !!

    For next step, I used another amplifier after power detector, the output is shown in attached file. The pules width is around 50ns, if I could convert this signal to  the pulse the problem has been solved!

Reply
  • Hi,

    I tried your circuit for my design but It didn't work. I prepared the PCB and redesigned for AD8067 and AD8611 but tha output It's not acceptable!!!!

    I also tried to use only AD8611 ( I used an amplifier before comparator  and a HPF to remove DC component) but It didn't work. When I use the DC block, at the input of AD8611, the DC voltage increases at Pin 2 ( I also checked by adding a resistor (330ohm) after DC block capacitor (2.2nF) and ground but nothing changed !!

    For next step, I used another amplifier after power detector, the output is shown in attached file. The pules width is around 50ns, if I could convert this signal to  the pulse the problem has been solved!

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