Voice control circuit
Compandor with sampling and equalization
Dynamic noise reduction with logarithmic control Patent #: 4696044
ApplicationNo. 160023 filed on 02/23/1988
US Classes:381/106, With amplitude compression/expansion455/72For compression and expansion of message signal (i.e., companding)
ExaminersPrimary: Chin, Tommy P.
Foreign Patent References
International ClassesH04R 029/00
AbstractA programmable low voltage multi-band compression system suitable for use with hearing aids is described. Received audio signals are processed by a band split filter which separates the received audio signal into a plurality of frequency bands. A plurality of compressors coupled to the band split filter compresses each of the respective frequency bands. The output of the compressor are then summed to generate a composite audio signal. The compression ratio of each of the compressors is set, in response to a set of control signals, to a preselected independent value. The average gain of each of the compressors is set to a preselected level independently of the other compressors. In addition, the compression ratio of each compressor may vary with input signal level. Another set of control signals is employed for setting the gain of the compressor to provide a volume control function.