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Step 3Simulations
Here are the simulations that I ran from the previous netlist and they show the characteristics of the Spy Ear.
You'd notice the frequency response is not even which produces distortions in the output (see next pic).
But this is ok, because Spy Ear is designed to focus on speech. The main spectrum of speech is between 300 and 3000Hz and if you are trying to spy on someone's conversation as the package claims, the goal is to amplify speech frequencies while cutting out ambient noise.
There is an advantage of having a schematic for simulation because with a few clicks you can investigate the effect of modding the components without actually doing it physically. For example, if C1 and C2 are replaced with larger capacitors, like on the order of 100u, the response approaches HiFi (see last picture). HiFi requires that the frequency response be flat and wide.
You'd notice the frequency response is not even which produces distortions in the output (see next pic).
But this is ok, because Spy Ear is designed to focus on speech. The main spectrum of speech is between 300 and 3000Hz and if you are trying to spy on someone's conversation as the package claims, the goal is to amplify speech frequencies while cutting out ambient noise.
There is an advantage of having a schematic for simulation because with a few clicks you can investigate the effect of modding the components without actually doing it physically. For example, if C1 and C2 are replaced with larger capacitors, like on the order of 100u, the response approaches HiFi (see last picture). HiFi requires that the frequency response be flat and wide.
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Sep 30, 2009. 4:08 AMskandar
says:
merci +ok
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