JPS6133288B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a sound quality adjustment device. To configure one channel of a graphic equalizer, which is a type of sound quality adjustment device, it is sufficient to configure a circuit that satisfies the transfer function T(s) shown in the following equation. S is Laplace operator, ω ₀ is central angular frequency, Q
is the sharpness, K ₁ is the attenuation rate at the angular frequency ω ₀ ,
K ₂ is the amplification factor at the angular frequency ω ₀ . Therefore, when K ₁ and K ₂ are changed while ω ₀ and Q are constant, when K ₁ = K ₂ = 1, it is flat, and when K ₁ =
1, when K ₂ > 1, the frequency characteristic is boost, and when K ₁ > 1, K ₂ = 1, the frequency characteristic is cut (Fig. 1). Therefore, when trying to collect the circuits 1 ₁ to 1 _o of the above transfer functions T _1(s) to _{T o(s)} at various center frequencies to cover the audio band, simply the second
A cascade connection as shown in the figure can be considered, but this configuration causes noise and deterioration of distortion rate. The present invention has been made in view of this point, and it mixes the outputs of n transfer function circuits connected to the input terminals, each having a different center frequency, in phase, and
The present invention attempts to provide a multi-channel sound quality adjustment device in which input signals are mixed in reverse phase using a 1-fold or n+1-fold amplifier to reduce noise and distortion. Hereinafter, one embodiment of the present invention will be described with reference to FIG. 3 and subsequent figures. Transfer function T _{1 (s)} ~ Circuit 1 ₁ ~ _{T o (s)}
1 _o has its input section commonly connected to the input terminal,
The output is connected to the inverting input terminal of each mixer 2. Reference numeral 3 denotes an amplifier having an amplification factor of n-1 times, and is connected to the input terminal and the non-inverting input terminal of the mixer 2. The transfer function T _{o (s)} satisfies the following equation. n=1 to n, ω _o is the central angular frequency, Q _o is the sharpness, K _N1 is the attenuation factor at the angular frequency ω _o , and K _o2 is the amplification factor at the angular frequency ω _o . Then, the overall transfer function e ₀ /e _i is as follows. e ₀ /e _i =n-1-T _1(s) -T _2(s) -...-T _o(s)
... (3) With this, for example, when n=3, T _1(s) to _{T 3(s)}
In the case of =1, e ₀ /e _i =-1. Note that the amplification factor of the amplifier 3 may be set to n+1 times. In this case, the overall transfer function e ₀ /e _i is as follows. e ₀ /e _i =n+1−T _1(s) −T _2(s) −……−T _o(s)
(4) When n=3 and T _1(s) to _{T 2(s)} =1, e ₀ /e _i =. Further, in FIG. 3, the outputs of the circuits 1 ₁ to 1 _o are connected to separate inverting input terminals of the mixer 2, but they may be commonly connected to one inverting input terminal. Furthermore, the amplifier 3 multiplies this by n-1 or n+1.
In the case of a double anti-phase amplifier, all the outputs of the circuits 1 ₁ to 1 _o and the output of the amplifier 3 may be input to a common inverting input terminal of the mixer 2. In FIG. 4, according to equation (3), n=3, Q ₁ to _{Q 3} =
3, ω _1/2 〓〜ω _3/2 〓=500Hz, 1KHz, 2KHz
We show the characteristics for the case. The set gains at the center frequencies of curves a to f are shown in the following table.

[Table] From the above, according to the present invention, it is possible to realize a multi-channel sound quality adjustment device, and it is also possible to improve noise and distortion.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram for one channel, Fig. 2 is a block diagram of cascade connection, Fig. 3 is a circuit diagram of an embodiment of the present invention, and Fig. 4 is a case of three channels using the circuit of Fig. 3. FIG. 2...Mixer, 3...An amplifier with an amplification factor of n-1.

Claims (1)

[Claims] 1. In-phase mixing the outputs of n circuits each having a transfer function with a different center frequency and connected to an input terminal, and applying it to the input terminal using an n-1 or n+1 times amplifier. A sound quality adjustment device which amplifies an input signal and performs reverse phase mixing on the output, and wherein the n circuits have the following transfer function T _{o (s)} . However, S is the Laplace operator, Q _o is the sharpness, ω _o
is the central angular frequency, K _o1 is the attenuation rate at ω _o , K _o2
is the amplification factor at _ωo .