Noise reduction device of FM stereo tuner

摘要

PURPOSE:To form a natural stereoscopic sense by dividing a stereo difference signal generated from a circuit generating a stereo sum signal and the stereo difference signal into plural frequency bands and compensating the stereo difference signal lost by noise elimination processing with a retarded stereo sum signal. CONSTITUTION:A circuit 2 in an FM stereo tuner generates a stereo sum signal (L+R) and a stereo difference signal (L-R). Then the generated sum signal (L+R) and the difference signal (L-R) are divided into plural frequency bands in the same devided frequency and noise elimination processing is applied by a noise elimination circuit 3. The noise elimination circuit 3 eliminates a division stereo difference signal at a low level at every divided band to generate a 2nd stereo difference signal. Then a retarded signal (L+R)' of the divided stereo sum signal of the same divided band as the eliminated divided stereo difference signal (L-R)d is added to a 2nd stereo difference signal to generate a synthesis signal. Thus, the loss of the stereo difference signal accompanying elimination of noise components is compensated.