Title:
ELECTRONIC VOLUME CIRCUIT
Document Type and Number:
Japanese Patent JP3253512
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To adjust the level of an input signal in response to a control level by providing a variable reference voltage source, a DC generating circuit, a differential amplifier and a GCA and switching the output of the differential amplifier when a voltage of the variable reference voltage source reaches a prescribed value.
SOLUTION: When the voltage of a variable reference voltage source 7 reaches a voltage VA or below, a switching transistor(TR) 18 is conductive, a voltage at an output terminal 19 of a differential amplifier 15 goes to an L level, a voltage at an output terminal 19 of a GCA 10 goes to an L level to mute the GCA 10. The operation of the circuit differs on the order of the voltage VA, a conventional mute curve is drawn at a voltage over the voltage VA and the GCA is muted at a voltage below the voltage VA. The voltage VA is set to -50dB. The level of nearly -50dB is a limit of hearing. No step control is conducted for the level but muting is suddenly executed. Thus, 32-ways of steps are in use for a range of -50dB to 0dB, the step interval is made finner and then a natural sense of listening as a whole of the electronic volume is realized.
Inventors:
Katsumi Imai
Application Number:
JP4368896A
Publication Date:
February 04, 2002
Filing Date:
February 29, 1996
Export Citation:
Assignee:
Sanyo Electric Co., Ltd.
International Classes:
H03G3/10; H03G3/30; (IPC1-7): H03G3/10
Domestic Patent References:
| JP63269609A | ||||
| JP56117414A | ||||
| JP5685913A | ||||
| JP4319805A | ||||
| JP59172819A | ||||
| JP5788316U |
Attorney, Agent or Firm:
Masamasa Shibano