JPS62269520A - Fm receiver - Google Patents

Abstract

PURPOSE:To freely set sound quality in response to the request of a user by providing a control voltage level variable means operating a 2nd sound quality control means and varying a control voltage fed to a 1st sound quality control means so as to vary the sound quality variable quantity freely. CONSTITUTION:A DC control voltage signal VCO in response to a level of an input signal Vi is given to a control terminal via resistors 6, 7, 8 in a voltage control sound quality variable circuit 4, which varies the sound quality of an audio signal automatically. The audio signal through the circuit 4 is inputted to the 2nd sound quality control means, that is, a sound quality adjusting circuit 5, where the frequency characteristic of the audio signal is controlled by adjusting a variable resistor 53 in the circuit 5. On the other hand, a control terminal of the circuit 4 is connected to a slider of the variable resistor 10 via a resistor 9. One terminal of the variable resistor 10 is connected to ground, the other terminal is connected to a power supply Vc and the slider is interlocked with the slider of the variable resistor 53. That is, in response to the operation of the variable resistor 10, the level of the control voltage signal VCO fed to the voltage control sound quality variable circuit 4 is changed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an FM (frequency modulation) receiver, and in particular, to an FM (frequency modulation) receiver.
The present invention relates to a technique for varying the sound quality of an audio signal of a receiver.

[Conventional technology]

FIG. 4 schematically shows the configuration of an FM receiver as an example of a conventional type. In the figure, 1 indicates an antenna, and an input signal V captured by the antenna 1 is input to an FM tuner 2. The FM tuner 2 performs high frequency amplification, frequency mixing, intermediate frequency amplification, etc. to generate a composite signal, supplies it to the multiplexer 3, and also inputs the input signal Vi.
A DC voltage signal V3 corresponding to the level of is output. This voltage signal V, is divided by resistors 6 and 7 to produce a control voltage signal Vl,. The signal is then input to the voltage controlled sound quality variable circuit 4. The multiplexer 3 separates and extracts an audio signal, that is, a right signal R and a left signal, from the input composite signal, and supplies each signal to a voltage-controlled sound quality variable circuit 4. The voltage-controlled sound quality variable circuit 4 generates a control voltage according to the level of the input signal V, that is, a control voltage signal v'c.
It has a function of automatically varying the sound quality of audio signals R and L according to o. This voltage control sound quality variable circuit 4
The audio signals R+, L+ after the sound quality has been changed are input to the sound quality adjustment circuit 5' that manually adjusts the sound quality, and the frequency characteristics of the audio signals R1 and Ll are adjusted in the sound quality adjustment circuit 5'. Variable resistance (
(not shown).

FIG. 5 shows an example of the characteristics of the conventional FM receiver shown in FIG. and the audio frequency f, and (b) shows the relationship between f=10
The relationship between the audio signal level L and the level of the input signal V at kHz is shown. As shown in FIG. 5(b), the audio signal level I7 tends to decrease as the level of the input signal ■ decreases.

In low-level regions, that is, in weak electric fields, the noise level that occupies the effective signal bone becomes relatively high.
In order to prevent this, the audio signal level L is attenuated in the high range of the audio frequency f, as shown in Fig. 5(a), and the amount of attenuation is as large as the human input signal ■, the lower the level. It's getting bigger.

That is, in the conventional type shown in FIG.
It is now available in

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, the amount of automatic sound quality variation is constant, while the amount of manual sound quality variation by the sound quality adjustment circuit 5' has an upper limit and a lower limit. However, even if an attempt is made to emphasize the high range through manual sound quality adjustment, there is an inconvenience in that the high range cannot be emphasized sufficiently, and there is a problem in that it is not possible to set the sound quality according to the user's preference. For example, in conventional configurations, high audio frequencies are compromised in order to relatively reduce the level of noise heard during weak electric fields; however, some users find this to be sufficient, while others There were cases in which users wanted to increase the high frequency level even if a small amount of noise was mixed in, and such requests could not be fully met.

The present invention was created in view of the problems in the conventional type described above, and an object of the present invention is to provide an FM receiver that can freely set the sound quality according to the user's request.

[Means for solving problems]

According to the present invention, a first sound quality control means (for example, a sound quality variable circuit) that automatically varies the sound quality of an audio signal by a control voltage according to the level of an input signal; An FM receiver comprising a second sound quality control means (for example, a sound quality adjustment circuit) that varies the frequency characteristics of the audio signal based on an external operation,
There is provided an FM receiver characterized by comprising means (for example, a variable resistor) for varying the level of the control voltage in conjunction with the second sound quality control means.

[For production]

In the FM receiver according to the present invention, when the control voltage level variable means is operated, the second sound quality control means is operated in conjunction with this, and the control voltage applied to the first sound quality control means is made variable. Since the amount of variable sound quality can be changed freely and the frequency characteristics of the audio signal that has passed through the first sound quality control means can be changed, the sound quality of the audio signal can be freely set according to the user's wishes. Become.

〔Example〕

FIG. 1 shows the configuration of an FM receiver as an embodiment of the present invention, and FIG. 2 shows the configuration of the main parts of the device shown in FIG. 1.

In FIG. 1, 1 indicates an antenna, and an input signal V, captured by the antenna 1, is input to an FM tuner 2. F
The M tuner 2 performs high frequency amplification, frequency mixing, intermediate frequency amplification, etc. to generate a composite signal, supplies it to the multiplexer 3, and outputs a DC voltage signal V according to the level of the input signal V. do. The multiplexer 3 separates and extracts an audio signal, that is, a right signal R and a left signal R, from the input composite signal.
It has a function of supplying each signal to the first sound quality control means, that is, the voltage-controlled sound quality variable circuit 4 (4R, 4L), and the voltage-controlled sound quality variable circuit 4 outputs a direct current according to the level of the input signal V. The control voltage signal V, .

It has a function of automatically varying the sound quality of audio signals R and L. The audio signals that have passed through the voltage-controlled sound quality variable circuit 4, that is, the audio signals R, L after the sound quality has been changed, are manually inputted to the second sound quality control means, that is, the sound quality adjustment circuit 5 (5R, SL), and the sound quality is adjusted. By adjusting the variable resistor 53 (see FIG. 2) in the circuit 5, the frequency characteristics of the audio signals R7 and Ll are controlled.

On the other hand, the FM tuner 2 receives a DC voltage signal V.

An input resistor 6 is connected to the input resistor 6, and this resistor 6 is connected to a resistor 7.
A resistor 8 is connected to the connection point of resistors 6 and 7.
One end of the resistor 8 is connected, and the other end of the resistor 8 is connected to the control terminals of amplifiers 43 and 44 (see FIG. 2) in the voltage controlled sound quality variable circuit 4, and is connected to the variable resistor 10 via a resistor 9.
is connected to the slider. One end of the variable resistor 10 is grounded, the other end is connected to the power supply VC, and the slider is adapted to interlock with the slider of the variable resistor 53 in the sound quality adjustment circuit 5. That is, the control voltage signal ■ is applied to the voltage-controlled sound quality variable circuit 4 in accordance with the operation of the variable resistor lO. . It is configured so that the size of the image can be changed.

Next, the configuration shown in FIG. 2 will be explained.

Although the example in FIG. 2 shows only the case where the audio signal is the R signal, the configuration is the same for the case of the L signal, so the illustration thereof is omitted.

The voltage control sound quality variable circuit 4R receives a variable control voltage signal VC.
An amplifier 43 (amplification degree K) that amplifies the audio signal R by changing the amplification degree according to An amplifier 44 (
an adder 45 that adds the output signals of the amplifiers 43 and 44; and a buffer amplifier 46 that buffers the audio signal that has passed through the adder 45, that is, the audio signal R1 after the sound quality has been changed; , consists of. On the other hand, the sound quality adjustment circuit 5R includes a resistor 51 whose one end is connected to the output side of the buffer amplifier 46 and whose other end is the output R1 of the FM receiver, and a capacitor whose one end is connected to the other end of the resistor 51. 52 and one end is capacitor 5
a variable resistor 53 connected to the other end of 2 and whose other end is grounded;
It consists of As shown by the broken line, the variable resistor 53
The slider of the variable resistor 10 is adapted to interlock with the slider of the variable resistor 10. Therefore, considering both the R signal and the L signal, the three variable resistors are configured to work together.

In this example, a triple volume was used as the three variable resistors.

Figure 3 shows an example of the characteristics of the FM receiver shown in Figure 1, where (a) shows the magnitude of the DC voltage signal ■, depending on the level of the input signal ■, and the voltage control sound quality variable. The relationship between the level of the control voltage signal Ve (1) applied to the circuit 4 is shown, and (b) shows the relationship between the level of the input signal ■, when the audio frequency is 1QkHz, and the level L, 12 of the audio signal R2. , and (c) shows the relationship between the level of the input signal V and the level LRI of the audio signal R1 when the audio frequency is 1QkHz.The broken line portion S shown in (a) is the saturation point of syllable control, In other words, this corresponds to the point where the frequency characteristics change flatly (see Figure 5 (a)), and even if a control voltage signal with a magnitude exceeding this level is applied, the audio signal level will remain L.
This means that there is no change. Also, ■, ■, c)
indicate high, intermediate, and low sound quality, respectively, and correspond to the position of the slider of the variable resistor 10 shown in FIG.

The operation of the apparatus of this embodiment will be described below with reference to FIGS. 1 to 3. Let us now consider the case where the slider of the variable resistor 10 is in the position ■ as a reference.

(1) When the slider of variable resistor 10 is adjusted to position e, in this case, variable resistor 1. Since the partial voltage ratio of O increases, the control voltage signal ■,. increases compared to the case of O (see Figure 3 (a)), which increases the high frequency level in the weak electric field in R8 (see Figure 3 (c)).
. In addition, since the resistance value of the variable resistor 53 increases in conjunction with the operation of the variable resistor 10, the high frequency level LII2 of the audio signal R2 increases compared to the case (2) (Fig. 3 (b)
)reference).

(2) When the slider of the variable resistor 10 is adjusted to the position (■) In this case, contrary to the case (1), the voltage division ratio of the variable resistor 10 becomes small, so the magnitude of the control voltage signal VCO is O (See Figure 3(a)). As a result, the high-frequency level at the time of a weak electric field decreases in R5 (the third
(See figure (c)). Furthermore, since the resistance value of the variable resistor 53 becomes small, the high frequency level L112 of the audio signal R2 is reduced compared to the case (2) (see FIG. 3(b)). Therefore, sufficient sound quality can be obtained even in a weak electric field by emphasizing the high range.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to arbitrarily set the sound quality according to the user's request.

[Brief explanation of the drawing]

1 is a diagram showing the configuration of an FM receiver as an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of the main part of the device shown in FIG. 1, and FIG. 3 is a diagram showing the configuration of the main part of the device shown in FIG. 1. FIG. 4 is a diagram showing the configuration of an FM receiver as an example of a conventional type; FIG. 5 is a diagram showing an example of characteristics by the device shown in FIG. 4. . 4.4R, 4L... Voltage control sound quality variable circuit, 5, S
R, 5L...Sound quality adjustment circuit, 10...Variable resistor,
53...Variable resistance, ■,...Input signal,
VCO...control voltage, R, L, R++L++Rz
tLt...Order Io signal.

Claims (1)

[Claims] First sound quality control means for automatically varying the sound quality of an audio signal using a control voltage according to the level of an input signal; and frequency characteristics of the audio signal that has passed through the first sound quality control means. a second sound quality control means for varying the level of the control voltage based on an external operation; Features FM receiver.