DRV135: Does TI have long-distance sound detection/recording solution?

Hi Jason,

detect sound with a microphone? What means "80dB at about 5cm"?

So, you would mean a simple audio band amplification of a microphone's signal and a Schmitt trigger? Or adding a signal rectifier and a low pass filter in front of the Schmitt trigger?

Kai

I mean 80 dB SPL at 5 cm away from the sound source, so about 25 dB SPL at 30 m place.
I am actually looking for a simple audio amplification of a microphone's signal, I haven't considered about Schmitt triger and rectifier since I think the amplifier is a module and I just care about the whole module's performance. I have seen some of the TI sample designs for audio application and I wonder if TI has long-distance sound detection solution

Hi Jason,

I'm not aware of a design or solution specifically for long-distance sound detection. For the microphone front-end portion of this, you might want to look at tidu765. That design uses OPA172 as an op amp for an electret microphone. If this design doesn't give enough gain, you might need to follow it up with a secondary gain stage, either with another OPA172, or another amplifier such as OPA1678.

If all you're looking for is a threshold detection of an audio signal, I think Kai's suggestion of a simple Schmitt trigger is a good solution. It may not even be necessary to use a peak detector, as long as you can latch the comparator output when it triggers. 

Thank you, I would like the micro-controller to do ADC sampling and further process of the sound signal the mic module receives. So circuit electronic noise suppression is necessary, in the design file you recommended to me I saw an RC filter at the output. 

Hi Jason,
This design is going to depend largely on what microphone you are using for the detection. This would dictate the required gain for the amplifier. Filtering to reduce noise should be relatively straightforward. For typical audio applications, you can use an RC filter with a cutoff frequency of ~20-30kHz, which should reduce any higher-frequency RF interference while preserving the audio band. If your signal of interest is lower in frequency within the audio band, you could reduce that cutoff frequency further.