472khz ultrasoic preamp

[carp3]

472khz ultrasonic preamp

Hi,
i have a schematic for 471khz (ultrasonic mic)preamp. but as far as i tested this circuit only response to 471khz. but my input frequency is between ~420khz and ~520khz. i don't know how to modify this circuit to have linear amplify for my frequency range. currently it amplify 471khz ~100 times (20mv p-p in, 2v p-p out) but it's not same for 430 or 420 khz ( around 70 and 50 times ) . i want linear gain for my range. and also filtering any other frequency. (bandpass).

any suggestion ?


(sorry for english)


my schematic:

supply voltage is 5v.


thanks.

 

[chuckey]

There is nothing in the supplied circuit diagram that will "tune" the circuit. At a guess it will be flat between 10s of KHZ and 10s of MHZ.
Frank

 

[carp3]

is there any possibility that the output load affect frequency response ?

 

[FvM]

is there any possibility that the output load affect frequency response ?

Only if you connect a tuned circuit. I would rather expect that the ultrasonic transducer restricts the bandwidth.