Granted Patent B2

US 8,150,070 · App. 11/984,598 · Granted Apr 3, 2012

Abstract

Claims (37)

1. A sound signal equalizer for adjusting gain in each of first to n th (where n is an integer of 2 or higher) frequency bands of an initial sound signal, the circuit comprising:

first to n th extraction circuits that are provided in corresponding fashion to the first to n th frequency bands and that extract and output a corresponding frequency band component of the initial sound signal,

first to n th gain adjustment circuits that are provided in corresponding fashion to the first to n th extraction circuits and that adjust the gain of an output signal of the corresponding extraction circuit and generate first to n th sound region adjustment signals

a synthesizing circuit that can synthesize the first to n th sound region adjustment signals in the initial sound signal,

a first filter as a one-sided band pass filter provided with prescribed characteristics selected from high-pass characteristics and low-pass characteristics, the sound signal equalizer including first to (n−1) th filters; and

a k th filter that has a wider pass band than a (k−1) th (wherein k is an arbitrary integer that satisfies the expression 2≦k≦n−1) filter, and that is the one-sided band pass filter, wherein

the first extraction circuit extracts the first frequency band component from the initial sound signal with the aid of the first filter;

the k th extraction circuit generates a difference between the output signal of the k th filter and the output signal of the (k−1) th filter for the initial sound signal, and outputs the difference as the k th frequency band component in the initial sound signal, and

the n th extraction circuit generates a difference between the initial sound signal and the output signal of the (n−1) th filter, and outputs the difference as the n th frequency band component in the initial sound signal.

2. The sound signal equalizer of claim 1 , wherein the first filter and the k th filter are configured using switched capacitor filters.

3. The sound signal equalizer of claim 2 , wherein the first to (n−1) th filters are provided with a resistor R and a capacitor C for adjusting the filter characteristics, and are RC active filters in which the resistor R and capacitor C synergistically contribute to a cutoff frequency; and

the resistor R is configured as equivalent resistance produced by a switched capacitor.

4. The sound signal equalizer of claim 3 , wherein the first to (n−1) th filters are formed as an integrated circuit on a semiconductor substrate.

5. The sound signal equalizer of claim 1 , wherein a tone control process for adjusting the strength of a high sound region and a low sound region of the initial sound signal is carried out in a case in which the term n is 2.

6. A signal equalizer for adjusting gain in each of first to n th (where n is an integer of 2 or higher) frequency bands for an initial signal, the circuit comprising:

first to n th extraction circuits that are provided in corresponding fashion to the first to n th frequency bands and that extract and output a corresponding frequency band component of the initial signal,

first to n th gain adjustment circuits that are provided in corresponding fashion to the first to n th extraction circuits and that adjust the gain of an output signal of the corresponding extraction circuit and generate first to n th adjustment signals,

a synthesizing circuit that can synthesize the first to n th adjustment signals in the initial signal,

a first filter as a one-sided band pass filter provided with prescribed characteristics selected from high-pass characteristics and low-pass characteristics, the sound signal equalizer including first to (n−1) th filters; and

a k th filter that has a wider pass band than a (k−1) th (wherein k is an arbitrary integer that satisfies the expression 2≦k≦n−1) filter, and that is the one-sided band pass filter, wherein

the first extraction circuit extracts the first frequency band component from the initial sound signal with the aid of the first filter;

the k th extraction circuit generates a difference between the output signal of the k th filter and the output signal of the (k−1) th filter for the initial sound signal, and outputs the difference as the k th frequency band component in the initial sound signal, and

the n th extraction circuit generates a difference between the initial sound signal and the output signal of the (n−1) th filter, and outputs the difference as the n th frequency band component in the initial sound signal.

7. The sound signal equalizer of claim 1 , wherein the first filter and the k th filter are low-pass filters,

the k th extraction circuit includes a first inverting circuit for inverting the output signal of the (k−1) th filter and a first adding circuit configured to have as inputs the output signal of the k th filter and the output of the first inverting circuit and output the k th frequency band component in the initial sound signal, and

the n th extraction circuit includes a second inverting circuit for inverting the output signal of the (n−1) th filter, and a second adding circuit configured to have as inputs the initial sound signal and the output of the second inverting circuit and output the n th frequency band component in the initial sound signal.

8. The sound signal equalizer of claim 6 , wherein the first filter and the k th filter are low-pass filters,

the k th extraction circuit includes a first inverting circuit for inverting the output signal of the (k−1) th filter and a first adding circuit configured to have as inputs the output signal of the k th filter and the output of the first inverting circuit and output the k th frequency band component in the initial sound signal, and

the n th extraction circuit includes a second inverting circuit for inverting the output signal of the (n−1) th filter, and a second adding circuit configured to have as inputs the initial sound signal and the output of the second inverting circuit and output the n th frequency band component in the initial sound signal.

9. The sound signal equalizer of claim 1 , wherein the first filter and the k th filter are high-pass filters,

the k th extraction circuit includes a first inverting circuit for inverting the output signal of the (k−1) th filter and a first adding circuit configured to have as inputs the output signal of the k th filter and the output of the first inverting circuit and output the k th frequency band component in the initial sound signal, and

the n th extraction circuit includes a second inverting circuit for inverting the output signal of the (n−1) th filter, and a second adding circuit configured to have as inputs the initial sound signal and the output of the second inverting circuit and output the n th frequency band component in the initial sound signal.

10. The sound signal equalizer of claim 6 , wherein the first filter and the k th filter are high-pass filters,

the k th extraction circuit includes a first inverting circuit for inverting the output signal of the (k−1) th filter and a first adding circuit configured to have as inputs the output signal of the k th filter and the output of the first inverting circuit and output the k th frequency band component in the initial sound signal, and

the n th extraction circuit includes a second inverting circuit for inverting the output signal of the (n−1) th filter, and a second adding circuit configured to have as inputs the initial sound signal and the output of the second inverting circuit and output the n th frequency band component in the initial sound signal.

11. The sound signal equalizer of claim 1 , wherein the synthesizing circuit has as inputs the initial sound signal, the output from a high sound region adjustment circuit, and the output from a low sound region adjustment circuit.

12. The sound signal equalizer of claim 6 , wherein the synthesizing circuit has as inputs the initial sound signal, the output from a high sound region adjustment circuit, and the output from a low sound region adjustment circuit.

Assignments (9)