How to amplify the signal output UG-032
Dear
I need help to make a specific application with development kit the Evaluation Board User Guide UG-032.
I need to increase the signal intensity by up to 110dB, this is made possible in sigmastudio using a second-order filter Medium Size Eq, but the hardware does not support, because their outputs are limited by their reference voltage amplifiers in 2.5 V, because the circuit power.
I wonder if there is any extension board or another type of amplifier that can be connected allowing for the increase of the signal level up to 110dB.
Thank you!
Hello,
By "110 dB," I'm assuming you would like to amplify the analog output of your -144x eval board to drive typical speakers to a sound pressure level (SPL) approaching 110 dB. That's about 20 dB higher than the OSHA 8-hour factory limit, while 20 dB lower than the threshold of pain.
The eval boards' DACs are equipped with the active filter shown below. This can drive headphones directly, and can be amplified with just about anything you have handy -- active computer speakers, for example. I've used various inexpensive computer speakers, the "2.1" sub-woofer variety work especially well. As you have found out, the DAC reference (as well as its output impedance) won't allow power amplification within the DSP -- this must be done externally.
If you're looking to design an amplifier into your final system, you have many choices depending upon how much DC power you have available, what speakers you're driving, and how much low end you're looking for. For the same SPL, bass frequencies below 100 Hz need much more power. Thus there's quite a range of possible amplifier ICs that may work for you.
At the low-power end, a SSM2306 driving a pair of efficient 4-ohm speakers can make quite a racket while sipping little current at only 5 volts in a battery-powered application. Below shows a typical application circuit (from the ADAU1701 mini eval board).
Need more? Try the SSM3302 with a 12V supply. This driving a pair of 8" speakers should get you plenty of volume with decent bass. An evaluation board EVAL-SSM3302Z is available.
Best regards,
Bob
Hello Bob,
Thank you for helping!
I'm doing a hearing test with this kit. So I need a signal strength output as high.
I believe that for my application, I'll need the SSM3302 with a 12V supply, in order to generate a signal with an intensity of up to 110 dB.
I'll do this test with the typical application you suggested and I will observe the results. If I have any questions, I'll contact.
Once again, thank you!
Best regards,
Ana
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