| 摘要 |
1517728 Companders PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 10 Oct 1975 [15 Oct 1974] 41626/75 Heading H4R A circuit providing complementary transfer functions, particularly for noise reduction, includes followers T 1 , T 2 selectively operable 5 to apply inputs 1 or.2 to respective impedances Z 1 , Z 2 , a current mirror T 3 , T 4 causing the current through one impedance to be reflected in the other. In record/playback apparatus, an input at 1 is transferred to output 3 for monitoring and to recording output 4 with gain Z 2 /Z 1 . With switch 5 reversed, the playback signal at 2 appears at 4 unmodified and at 3 with gain Z 1 /Z 2 . Impedance Z 2 may be complex as in Specification 1,431,481. |
