Dual input microphone preamp with far field noise suppression, SNR enhancement & earpiece driver

The LMV1099 is an uplink and downlink voice intelligibility enhancing analog IC, ideally suited for mobile handsets. Uplink voice intelligibility is improved by rejecting far-field noise through a unique two-microphone solution. Downlink voice intelligibility is improved by enhancing the SNR (Signal-to-Noise Ratio) between the downlink voice and the ambient noise environment at the user’s earpiece.

The LMV1099 preserves uplink near-field voice signals within close range of the microphones while rejecting far-field acoustic noise greater than 0.5m from the microphones.

The LMV1099 also enhances downlink voice intelligibility by improving near-field SNR based on the user’s environment. The analog circuitry adapts dynamically to both the user’s ambient noise environment as well as the downlink signal amplitude to ensure optimum SNRI (signal-to-noise ratio improvement). The downlink path also provides uplink noise attenuation through an adjustable high pass filter before the SNR enhanced downlink voice reaches the user’s earpiece.

Unlike digital-based noise reduction solutions, the all-analog low power consuming LMV1099 increases both uplink and downlink voice intelligibility without DSP-type artifacts, distortions or processing delays.