JPS60185413A - Variable resonance type equalizing system - Google Patents

Abstract

PURPOSE:To control the resonance frequency and the sharpness of resonance with simple constitution by providing an analog arithmetic means to a control section, detecting the difference of a detected output of high and low frequencies among plural detected outputs and generating a control signal of the resonance frequency. CONSTITUTION:A resonator 5 consists of a variable resistor R51, a variable capacitor C52, and an inductance L53, the resonance frequency fr and the resonance sharpness Q are controlled and an input signal is ouputted while being made almost flat. An AGC amplifier (AGC) 6 forms an output signal while making the level of an output signal of the resonator 5 constant. A filter detector 7 consists of band pass filters BPFa71, BPFb72 and BPFc73 detecting three frequency components f+, f0, f- arranged at an equal interval in the band from the output signal. Detected outputs V+, V0, V- are outputted to a controller 8. The controller 8 consists of operational amplifiers OPAa81, OPAb82, OPAc83 and a synthesizer 84.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a variable resonant equalizer, and particularly to a variable resonant equalization method using analog control.

(2) Background of the Technology When transmitting digital information, if the signal is distorted and propagated due to fading or the like, it becomes difficult to reproduce the information accurately. In particular, highly efficient modulation methods such as multilevel QAM are susceptible to this effect. Therefore, the received signal converted to ■F is demodulated after equalizing the distortion caused by fading so that it has uniform characteristics within the transmission band. There is a variable resonant equalizer as an equalizer used in this method. A variable resonant equalizer has a resonator that can change the resonant frequency (fr) and sharpness (Q), and has a resonant characteristic that is the opposite of the frequency characteristic distorted by fading that occurs in the propagation path. This is an equalizer that controls the rr and Q of the resonator. This control tends to require extensive control, and a variable resonance type equalization system that is simple in structure and highly effective is desired.

(3) Conventional technology and problems A conventional variable resonant equalizer will be described below.

FIG. 1 is a block diagram of a conventional variable resonant equalizer. In the figure, 1 is a resonator (R2H).

3 2 is AGC amplifier (8QC), 3 is II] wave detector (3
fDE'T'), 1 is micro': 1 mpyo 4-ri (μ
mCOM) respectively.

Fig. 2 is an explanatory diagram of the operation of the variable resonant equalizer shown in Fig. 1. (81 is the spectrum I/ram of the input signal, the solid line is the spectrum I/ram that does not receive distortion, and the broken line is the transmission (h) is the characteristic of the resonator, and (C) is the spectrum of the output signal after equalization.

In Fig. 1, the resonator (R2H) 1 has a variable resonance frequency [and sharpness Q], and the distortion of the spectrum of the input signal as shown in the dotted line in Fig. 2 (a) and the inverse characteristic are shown in Fig. 2. (
fr and Q are controlled so as to have the resonance characteristics shown in b), and the output is made with the input voltage almost flat. The level of the output signal of C amplifier (A, cc) 2 & J resonator (R2H) 1 is kept constant to produce an equalized output signal as shown in FIG. 1(C). A private wave detector (3f DIET) 3 detects three frequencies f+, f□, f arranged at equal intervals within the band from the equalized output signal.
Detect the component of (fl>fo >f), and the f+, fo
, f-, respectively, are outputted to a microcomputer (μmCOM) 4. Microcomputer (/J-COM) 4 is a resonator (R2
H) Voltages V1 and V that control fr and Q of l are output, and unless the levels of V, -, Vo, and V- are equal to each other, V, , -, V, , V - Estimate the deviation of fr and excess or deficiency of Q from the relative level difference of V
+, VO, V- are equal to each other (3fDET>
Output of 3■ Since a computer was used as a controller to control fr and Q from 10, vo, v-, an A/D converter to convert the voltage into numerical values and a D/A to generate voltage from the numerical values were used. A large amount of hardware such as converters, various memories used for calculations, and complex software I- to estimate the deviation of fl- and the excess or deficiency of Q from the relative level differences of V-+, VO, and V-. Air was needed. Therefore, the cost increases, the power consumption increases, and the device becomes larger. There were drawbacks such as.

(4) Object of the Invention An object of the present invention is to eliminate the above-mentioned conventional drawbacks and to provide a variable resonant equalization method that can control the resonant frequency and resonance sharpness of a resonator with a simple configuration.

(5) Structure of the Invention According to the present invention, the above object is achieved by inputting a received signal into a resonator, detecting a plurality of frequency components within a transmission band from the output of the resonator, and controlling the plurality of frequency components in a control section. The detection output causes the resonant characteristics of the resonator to have frequency characteristics opposite to the input distortion.
In a radio device that equalizes input distortion by controlling the resonant frequency and sharpness of resonance of the resonator, and demodulates the equalized output by the resonator, the control section is provided with an analog calculation means, and the plurality of Of the detection outputs, the difference between the high-frequency detection output and the low-frequency detection output is calculated to create a control signal of the resonance frequency, and the sum or sum of some of the plurality of detection outputs is calculated. This is achieved by providing a variable resonance type equalization method characterized in that a difference is calculated to create a control signal for the sharpness of the resonance.

(6) Examples of the invention Examples of the present invention will be described below.

FIG. 3 is a block configuration diagram of a variable resonant equalizer according to an embodiment of the present invention, in which 5 is a resonator, 51 is a variable resistor (R), 52 is a variable capacitor (C), and 53 is an inductor 7. (T-), 6 is an AGC amplifier (AGC), 7 is a small wave detector, 71 is a first bandpass filter (BPFa), 7
2 is a second band pass filter (BPFb), 73 is a third band pass filter (BPFc), 8 is a controller, and 81 is a first band pass filter.
operational amplifier (OPAa), 82 second operational amplifier (
OPAb), 83 is the third operational amplifier (OPA, c),
84 and 84 respectively indicate synthesizers.

Figure 4 is an explanatory diagram of the operation of the variable resonant equalizer in Figure 3, where (a) is the spectrum output from the AGC amplifier 6 of the equalization section, where the solid line is when there is distortion and the broken line is when there is no distortion. case,
(b) is the resonance characteristic of the resonator 5 after f and Q are controlled, (C) is the spectrum of the output of the A, G C amplifier 6 after equalization, the horizontal axis is the frequency, and the vertical axis is the resonance characteristic of the resonator 5. Axis 6; j indicates amplitude.

(In Figure 3, resonator 5CJ'', variable resistor (R1)
51. Variable capacitance (C) 52. and inductance (L)
53, the resonant frequency fr and the sharpness of the resonance are controlled to be 0, and the input signal wave is made substantially flat and outputted. A
C'', C amplifier (AGC > 6 makes the level of the output signal of the resonator 5 constant and output signal, 3. The radio frequency detection base 7 is 4; Three frequencies f in a row, fO, f (f4>fo
>f~) component is detected. Second. Third bandpass 1 wave filter (BPF, -171, I'3PFb72, BP
Fc73), and the respective detection outputs V1-, (, V- are output to the controller 8. O.P.A.
a81. ○PAL+82, 0PAc83) and a synthesizer 84, 0PAa3] 4;l:A (V
-1--V-) (8 represents interest fl), ○PAb82
is A (V-1--V6), 0PAC83! ;l'
, A (V----Vo), and A (V-1
−−V−, ) is the voltage ■key that controls the fl− of the resonator 5.
807-1---Vo) and A, (V---
VO) L: Voltage ■ which is synthesized by the 1 synthesizer 84 and controls Q. is output as In the resonator 5, C becomes large as ``■'' becomes large, and R becomes large as Vo becomes large.

For example, as an input to the variable resonant equalizer in FIG.
(V-(---VO)-l-A, (V---Vo)>
O, V7 (=A, (V + V-)) increases and becomes louder, so fr (=1/2πJ7E)
is low, and Q(-R/jT7) is large. Therefore, the resonance characteristics become as shown in FIG. 4(1)), and the input distortion is equalized, resulting in a substantially flat output of schemata 1 to ram as shown in FIG. 4(C).

In this embodiment, the operational amplifier (OPAb) 82 and the operational amplifier (O]) Ac) 83 are combined as they are, but they may be combined selectively by inserting diodes into the outputs of both operational amplifiers. .

Further, in this embodiment, three frequencies are detected from the output of the AGC amplifier 6, and the resonance frequency f, - and the resonance sharpness Q are detected.
The number of frequencies to be detected is not limited to three, for example, five frequencies (f, , fa, f3, f
4-, f5; fl < r2 < f B < f 4.
< f 5 ), and the respective detection outputs (V,
, V□, VB, Vq, V5) to ■(,.

VO・Vq, = A (Vg V−+, ) −+−A (
Vq-■λ)VQ =A (Vq v3) "A (V car ■3)+-A (Vq V-3) +A (V!;-
VB).

(7) Effects of the Invention According to the present invention, as described above, the resonant frequency and resonance sharpness of the resonator can be controlled by a very simple circuit using an operational amplifier, so the cost is reduced. cheap,
A great effect can be obtained in that a small variable resonant equalizer with low power consumption can be created.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional variable resonant equalizer, Fig. 2 is an explanatory diagram of the operation of the variable resonant equalizer shown in Fig. 1, and Fig. 3 is a variable resonant equalizer according to an embodiment of the present invention. FIG. 4 is a block configuration diagram of an equalizer, and an explanatory diagram of the operation of the variable resonant equalizer of FIG. 3; In the drawing, 1 and 5 are variable equalizers, 51 is a variable resistor, 52 is a variable capacitor, 53 is an inductance, 2 and 6
Ll: AGC amplifier, 3 and 7 are wave detection/on-base, 71.72 and 73 B) 1 pass filter, 4 is a controller using a microcomputer, 8 is a control using an operational amplifier 81. 82 and 83 are operational amplifiers, 84
indicate the synthesizer, respectively. 】0 小'e 欝V ≠゛Birod (♂ 斡1e special attack' beg

Claims (1)

[Claims] A received signal is input to a resonator, a plurality of frequency components within the transmission band are detected from the output of the resonator, and the control section uses the plurality of detection outputs to make the resonance characteristic of the resonator opposite to the input distortion. In a radio device that equalizes input distortion by controlling the resonant frequency and sharpness of resonance of the resonator so as to have the same frequency characteristics, and demodulates the equalized output of the resonator, the controller includes an analog calculation. means for calculating the difference between the detection output of the high frequency range among the plurality of detection outputs to create a control signal of the resonance frequency; A variable resonance type equalization method characterized in that a control signal for the sharpness of the resonance is created by calculating the difference or the difference.