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???
05/11/10 16:25
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 		 #175821 - So you're amplifying the noise?!
Responding to: ???'s previous message
Manju Arun said:
The input signal is 16mV AC @ 50Hz with lots of noise like 500-700KHz. My circuit contains only one amplifier with an effective gain of 127, a buffer of unity gain and an LPF.

Do you mean:
Save This Code
                    +-----+             +--------+ Buffered,   +--------+
 noisy 50Hz signal  |     | Amplified   |        | Amplified   |        |
------------------->+ Amp +------------>+ Buffer +------------>+ Filter +---> Output
                    |     | Noisy 50Hz  |        | Noisy 50Hz  |        |
                    +-----+             +--------+             +--------+


As Kai suggests, it's usually better to get rid of the noise as early as possible - rather than feed it through all the stages, and then try to filter it out at the end!

Why not just have a narrow-band amplifier?

List of 25 messages in thread
TopicAuthorDate
What is the use of buffer?            01/01/70 00:00      
   what is ...            01/01/70 00:00      
      LPF stage            01/01/70 00:00      
         Not helpful            01/01/70 00:00      
            Not talking on rogowski coil            01/01/70 00:00      
               Analogue filter design            01/01/70 00:00      
   Application Dependant...            01/01/70 00:00      
      Let me make it clear            01/01/70 00:00      
         RE: I got a review comment            01/01/70 00:00      
   You need to be more specific            01/01/70 00:00      
      "Buffer" can be used in several contexts            01/01/70 00:00      
         So it is an input buffer for impedance matching            01/01/70 00:00      
            You really should ask the one who said it!            01/01/70 00:00      
               Does it mean that the delay matching buffer not required            01/01/70 00:00      
                  What do you think?            01/01/70 00:00      
                     I think            01/01/70 00:00      
                        Right.            01/01/70 00:00      
                           one doubt            01/01/70 00:00      
                              Already answered            01/01/70 00:00      
                              Buffers...            01/01/70 00:00      
   It depends...            01/01/70 00:00      
   Peak to Peak is varying            01/01/70 00:00      
      Load regulation in generators?            01/01/70 00:00      
      Then put a filter in front of it!            01/01/70 00:00      
      So you're amplifying the noise?!            01/01/70 00:00      

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