AK2346B

The AK2346B is a one-chip IC that integrates the baseband section of a radio with a built-in audio filter, limiter, splatter filter, emphasis, compander, confidential circuit, and MSK modem.
The AK2346B has HPF for voice, shows high attenuation rate below 250Hz, and removes sub audio signal of CTCSS. 
In addition, a total of four electronic volumes are provided at the first and last stages of the transmitter / receiver, and it is possible to automatically adjust the microphone sensitivity and the sensitivity of the modulator / demodulator under the control of the CPU.