FM Multipath Noise Reduction Control IC for Car Radios

A major problem in mobile EM reception is multipath signal which causes a change in the amplitude of the radio signal. A method to improve the signal to noise ratio by modification of the frequency response and channel separation, has become available. This is customarily called the “Automatic High Cut and Blend” system.

When multipath occurs for a reasonably long time, slow introduction of the high cut and blend effect has little perceivable modification impact on the audio signal, yet the signal to noise ratios are greatly improved.

As a result of this research, a Control Voltage Generation Circuit has been developed in IC form. This IC allows for random selection of control voltage characteristics which allows its use in various FM receiver designs, permitting broad applications of this device by a design engineer.