Amplifiers – With control of power supply or bias voltage – With control of input electrode or gain control electrode bias
Patent
1974-08-19
1976-08-31
Mullins, James B.
Amplifiers
With control of power supply or bias voltage
With control of input electrode or gain control electrode bias
330 59, 330124R, 330136, H03G 702
Patent
active
039784231
ABSTRACT:
A dynamic expander which is particularly suitable for restoring the original dynamic range of prerecorded stereo sound program material is disclosed. In this embodiment, the expander comprises first and second variable gain amplifiers respectively coupled to a stereo input. The gain of the amplifiers is controlled by a common slow-attack, slow-decay time-constant circuit. An input of the time-constant circuit is coupled to the stereo input and the time-constant circuit responds thereto to provide a control signal which is indicative of the volume of the program material but which varies in accordance with the characteristics of a non-linear element in the time-constant circuit and with the slow-attack and slow-decay characteristics of the time-constant circuit. The control signal of the time-constant circuit drives a light-emitting-diode (LED) which, in turn, determines the resistance of a pair of matched, light-controlled-resistors (LCR's). Each LCR acts linearly and controls the gain of a respective one of the variable gain amplifiers in accordance with the resistance of that LCR.
REFERENCES:
patent: 2892891 (1959-06-01), Manley et al.
patent: 3119970 (1964-01-01), Thompson et al.
patent: 3333208 (1967-07-01), Hudak
patent: 3441867 (1969-04-01), Davison
patent: 3699468 (1972-10-01), Harmgardt
patent: 3700811 (1972-10-01), Davidson
patent: 3819957 (1974-06-01), Saeki et al.
B-Cubed Engineering, Inc.
Michals William J.
Mullins James B.
LandOfFree
Dynamic expander does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dynamic expander, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamic expander will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1818369