Electronics > Projects, Designs, and Technical Stuff
Piezo disc impedance matching
dmendesf:
First let's remember what impedance matching brings to us: when a source is matched to a receiver then you have the biggest transfer of POWER possible (and it's 50%). Question is: you don't want the power. You want the signal. So you need to maximize the signal to noise ratio, not the power coupled.
dimbmw:
--- Quote from: dmendesf on June 15, 2020, 03:38:41 am ---First let's remember what impedance matching brings to us: when a source is matched to a receiver then you have the biggest transfer of POWER possible (and it's 50%). Question is: you don't want the power. You want the signal. So you need to maximize the signal to noise ratio, not the power coupled.
--- End quote ---
I need maximum response (transmit->reflection from target->receive). I guess you can say that it's better to have max power.
On a side note, I don't think it has to be 50%. I can have the output impedance lower than 50 ohm, let's say 10 ohm, and can have better %.
dmendesf:
Power is V*I. If you put a voltage buffer at the sensor output then as long as you have enough current to drive the resistors and Op Amp input then you want to maximize the voltage, not the product V*I, so perfect power matching isn't what you need.
dmendesf:
Ok I think I got it: I'm talking about the receiver, you're talking about the transmitter. For transmission you want good matching, for receiving it's not important.
dimbmw:
--- Quote from: dmendesf on June 15, 2020, 01:18:23 pm ---Ok I think I got it: I'm talking about the receiver, you're talking about the transmitter. For transmission you want good matching, for receiving it's not important.
--- End quote ---
In my case the same transducer is transmitting and receiving, it is a pulse - echo setup.
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