Output level control apparatus

• US 4,926,485 A
• Filed: 01/05/1989
• Issued: 05/15/1990
• Est. Priority Date: 03/11/1988
• Status: Expired due to Term

• Current Assignee: Pioneer Electronic Corporation (Pioneer Corporation)
• Original Assignee: Pioneer Electronic Corporation (Pioneer Corporation)
• Inventors: Yamashita, Masayasu
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US07/293,784
• Time in Patent Office: 495 Days
• Field of Search: 360/46, 381/104, 381/105, 381/107, 381/108, 381/109, 381/28
• US Class Current: 381/107
• CPC Class Codes: H03G 1/0088 using discontinuously variable devices, e.g. switch-operated
• CPC Class Codes: H03G 7/007 of digital or coded signals

Abstract

An output level control apparatus which operates according to a reproduced signal level from a digital recording apparatus. The output level control apparatus includes a signal level detection device which compares the level of the reproduced signal with a predetermined level to decide if a level of the reproduced signal should be changed. The output level control apparatus further includes a device which attenuates the level of the reproduced signal to a suitable level when the signal level detection device determines that the reproduced signal should be changed.

Claims

1. An output level control apparatus which operates according to the level of a reproduced digital signal from a digital signal reproducing apparatus, the output level control apparatus comprising:

(a) signal level detection means which compares the level of the reproduced digital signal to be supplied to a digital attenuator with a predetermined reference level to determine if the level of the reproduced digital signal should be changed; and

(b) output signal level adjusting means which outputs a command signal representing an attenuation level to the digital attenuator when said signal level detection means determines that the level of the reproduced digital signal should be changed.

2. The output level control apparatus according to claim 1, further comprising a decoder for decoding the output of the digital reproducing apparatus, and a delay circuit connected to said decoder and to said digital attentuator, said delay circuit causing a delay of the output of said decoder for a period of time so that said output signal level adjusting means can output the command signal.

4. The output level control apparatus according to claim 1, wherein said signal level detection means and said output signal level adjusting means comprise a microprocessor having memory means for storing information representing a plurality of different attenuation levels, and wherein said command signal which is supplied to said attenuator represents one of said different attenuation levels.

5. The output level control apparatus according to claim 4, further comprising means for changing the information representing the plurality of different attentuation levels.

6. The output level control apparatus according to claim 5, wherein said changing means comprises a microprocessor coupled to said digital attentuator.

3. An output level control apparatus which operates according to a reproduced signal level from a digital reproducing apparatus, the output level control apparatus comprising:

signal level detection means which compares the reproduced signal level with a predetermined reference level to determine if the level of the reproduced signal should be changed;

output signal level adjusting means which outputs a command signal representing an attenuation level to a digital attenuator when said signal level detection means determines that the level of the reproduced signal should be changed; and

memory means for storing information representing a plurality of average output levels, the plurality of average output levels respectively corresponding to the average output levels reproduced from a plurality of different programs, and wherein the predetermined reference level is the lowest average output level of the average output levels stored in said memory means.

7. An output level control apparatus which operates according to the level of a reproduced digital signal from a digital signal reproducing apparatus, the output level control apparatus comprises:

(a) signal level detection means which compares the level of the reproduced digital signal to be supplied to a set of digital attenuators with a predetermined reference level to determine if the level of the reproduced digital signal should be changed; and

(b) selecting means for outputting a level setting which selects a suitable attenuator form the set of digital attenuators when said signal level detection means indicates that the level of the reproduced digital signal should be changed, each of said set of digital attenuators having a different attenuation characteristic.

8. The output level control apparatus according to claim 7, further comprising means for changing the attentuation characteristics of each of said set of digital attentuators.

9. The output level control apparatus according to claim 7, further comprising a plurality of digital to analog converters, each of the plurality of said digital to analog converters being connected to the output of a different one of said set of digital attentuators.

10. The output level control apparatus according to claim 9, wherein there are two digital attentuators and two digital to analog converters. and wherein the output of the digital signal reproducing apparatus represents a stereo phonic signal.