Circuit for digital processing of audio signals
First Claim
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1. A circuit for digital processing of audio signals in a vehicle radio receiver, comprising:
- a digital filter serving as a tone control of the radio receiver, said digital filter having a frequency response which is controllable responsive to supplied coefficients; and
a volume control for controlling a volume of the radio receiver responsive to control signals;
said digital filter having controllable low frequency, high frequency and medium frequency transfer profiles, said transfer profiles being controlled responsive to respective control signals such that when at least one of said high and low frequency transfer profiles of said digital filter is increased relative to said medium frequency transfer profile, said medium frequency transfer profile of said digital filter is decreased; and
a control signal corresponding to the decrease of the medium frequency transfer profile of said digital filter being supplied to said volume control to cause said volume control to compensate a volume of the vehicle radio receiver based on the decrease of the medium frequency profile of the digital filter;
whereby the decrease in the medium control frequency transfer profile of said digital filter normalizes a transmission factor for the at least one of the high and low frequency transfer profiles that was increased.
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Abstract
In a circuit for digital processing of audio signals in a radio receiver, preferably in a car radio, the audio signals pass through a digital filter designed as a tone control, whose frequency response can be controlled with supplied coefficients, and a volume control, whose transmission factor can be controlled with supplied control signals. If the high and/or low frequencies are raised, the transmission factor of the filter at medium frequencies can be correspondingly lowered. Volume control compensates for the reduction. The volume control may contain a digital and an analog portion.
28 Citations
7 Claims
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1. A circuit for digital processing of audio signals in a vehicle radio receiver, comprising:
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a digital filter serving as a tone control of the radio receiver, said digital filter having a frequency response which is controllable responsive to supplied coefficients; and a volume control for controlling a volume of the radio receiver responsive to control signals; said digital filter having controllable low frequency, high frequency and medium frequency transfer profiles, said transfer profiles being controlled responsive to respective control signals such that when at least one of said high and low frequency transfer profiles of said digital filter is increased relative to said medium frequency transfer profile, said medium frequency transfer profile of said digital filter is decreased; and a control signal corresponding to the decrease of the medium frequency transfer profile of said digital filter being supplied to said volume control to cause said volume control to compensate a volume of the vehicle radio receiver based on the decrease of the medium frequency profile of the digital filter; whereby the decrease in the medium control frequency transfer profile of said digital filter normalizes a transmission factor for the at least one of the high and low frequency transfer profiles that was increased.
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2. A circuit for digital processing of audio signals in a vehicle radio receiver, comprising:
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a digital filter connected to receive the audio signals, said digital filter serving as a tone control of the radio receiver, said digital filter having a frequency response which is controllable with supplied coefficients; and a volume control having a transmission factor that is controllable with supplied control signals; the volume control comprising; at least a first control element (101,
106) for controlling digital signals from the digital filter, said at least a first control element being connected to a digital/analog converter (102,
107), and at least one second control element (103, 104, 108,
109) for controlling the audio signals as the audio signals are processed by said circuit; andat least one of the supplied control signals being provided to the first and second control elements (101, 106, 103, 104, 108,
109) such that at least a first control element 101,
106) is operated with a maximum transmission factor; andwherein the digital filter has controllable low frequency, high frequency and medium frequency transfer profiles, said transfer profiles being controlled responsive to respective supplied control signals such that when at least one of said high and low frequency transfer profiles is increased relative to the medium frequency transfer profile of said digital filter, said medium frequency transfer profile is decreased. - View Dependent Claims (3, 4, 5, 6, 7)
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Specification