WO1997018624A1

WO1997018624A1 - Fm modulator

Info

Publication number: WO1997018624A1
Application number: PCT/JP1996/001705
Authority: WO
Inventors: Takeshi Ikeda; Akira Okamoto
Original assignee: Takeshi Ikeda; Akira Okamoto
Priority date: 1995-11-15
Filing date: 1996-06-20
Publication date: 1997-05-22
Also published as: TW297979B; AU6137796A

Abstract

An FM modulator (1) includes two phase shifting circuits (110C and 30C) and a capacitor microphone (14-1) is provided in the circuit (110C). The FM modulator (1) oscillates at the frequency at which the sum of the amounts of phase shift of the two circuits (110C and 30C) is 360°. When the capacitance of the microphone (14-1) is slightly changed by the sound pressure, the modulator (1) outputs FM signals from an output terminal (92) by directly utilizing the change for the frequency modulation.

Description

Edifice

FM modulator Technical field

TECHNICAL FIELD The present invention relates to an FM modulator for FM-modulating a sound and sending it out. Background art

The FM wireless microphone amplifies the sound collected by the microphone, performs FM modulation, amplifies the FM-modulated signal, and transmits it from the antenna. For this purpose, the microphone, low-frequency bandwidth circuit, and FM modulation It includes a circuit, a high-frequency amplifier circuit, and an antenna.

The FM modulation circuit is generally configured using an LC oscillator that generates a sine wave with little distortion. There are various types of LC oscillators such as Colpitts type LC oscillators. For example, the capacity of the LC resonance circuit included in the LC oscillator is composed of a varicap (variable capacitance diode), and the capacitance is the voltage of the FM modulation signal. FM modulation is performed by changing the level according to the fluctuation of the level.

However, this type of LC oscillator has the problem that if the oscillation frequency is greatly changed, the voltage level of the oscillation output also changes, and it is not practical as it is. Therefore, when using this type of LC generator, a circuit for keeping the amplitude of the FM carrier constant is required, and the circuit configuration becomes complicated. Disclosure of the invention

The present invention has been conceived to solve such a problem, and an object thereof is to provide an FM modulator having a simple circuit configuration.

The FM modulator of the present invention includes two all-pass type phase shift circuits including a differential amplifier and a CR circuit, and cascade-connects these two phase shift circuits to output the output of the phase shift circuit at a subsequent stage. To the input side of the previous phase shift circuit, and a condenser microphone as a capacitor in the CR circuit included in one of the two phase shift circuits. By using this, an FM-modulated signal is output from one of the two phase shift circuits. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a circuit diagram showing a configuration of an FM modulator of a first embodiment,

FIG. 2 is a diagram showing another configuration of the FM modulator,

FIG. 3 is a circuit diagram showing a configuration of an oscillator in which a capacitor microphone or the like included in the FM modulator shown in FIG. 1 is replaced with a capacitor having a fixed capacitance;

Fig. 4 is a vector diagram related to the input / output voltage etc. of the preceding phase shift circuit shown in Fig. 3, and Fig. 5 is a vector related to the input / output voltage etc. of the subsequent phase shifting circuit shown in Fig. 3. Fig. 6 is a circuit diagram showing the configuration of the phase shift circuit including the condenser microphone.

FIG. 7 is a circuit diagram showing a configuration of a phase shift circuit including an LR circuit,

FIG. 8 is a vector diagram relating to the input / output voltage of the phase shift circuit shown in FIG. 7, and FIG. 9 is a circuit diagram showing another configuration of the phase shift circuit including the LR circuit.

FIG. 10 is a vector diagram relating to the input / output voltage of the phase shift circuit shown in FIG. 9, and FIG. 11 is a circuit diagram showing a configuration of an oscillator having a voltage divider circuit in the phase shift circuit. FIG. 12 is a circuit diagram showing another configuration of the oscillator,

FIG. 13 is a circuit diagram showing a configuration of a phase shift circuit which can be replaced with the preceding phase shift circuit shown in FIG. 12,

FIG. 14 is a circuit diagram showing the configuration of a phase shift circuit that can be replaced with the subsequent phase shift circuit shown in FIG.

FIG. 15 is a circuit diagram showing a detailed configuration of an FM modulator according to a fourth embodiment. FIG. 16 is a circuit diagram showing a configuration of an oscillator including a phase inversion circuit.

FIG. 17 is a circuit diagram showing another configuration of an oscillator including a phase inversion circuit,

FIG. 18 is a circuit diagram for reducing the detailed configuration of the FM modulator according to the seventh embodiment, and FIG. 19 is a diagram illustrating a capacitor microphone and the like included in the FM modulator shown in FIG. Is a circuit diagram showing a configuration of an oscillator replaced with a fixed capacity,

FIG. 20 is a vector diagram relating to input / output voltages and the like of the preceding phase shift circuit shown in FIG. Figure 21 is a vector diagram related to input and output pressure of the subsequent phase shift circuit shown in Fig. 19,

FIG. 22 is a circuit diagram showing the configuration of a phase shift circuit including a condenser microphone, and FIG. 23 is a diagram showing the configuration of a phase shift circuit that can replace the preceding phase shift circuit shown in FIG.问 Road map,

Fig. 24 is a vector diagram of the input / output voltage etc. of the phase shift circuit shown in Fig. 23, and Fig. 25 is a phase shifter that can be replaced with the subsequent phase shift circuit shown in Fig. 19 A circuit diagram showing the structure of the circuit,

FIG. 26 is a vector diagram of the phase shift shown in FIG. 25 [port: input / output turret pressure of the road, etc.] FIG. 27 is a circuit diagram showing a configuration of an oscillator including a phase inversion circuit,

FIG. 28 is a circuit diagram showing another configuration of the oscillator including the phase inversion circuit,

FIG. 29 is a circuit diagram showing a configuration of the FM modulator according to the tenth embodiment. FIG. 30 is a diagram showing the FET and its peripheral circuits included in the FM modulator shown in FIG. Is a circuit diagram showing a configuration of an oscillator replaced with a fixed resistor,

FIG. 31 is a vector diagram relating to the input / output IS pressure and the like of the preceding phase shift circuit shown in FIG. 30;

FIG. 32 is a vector diagram relating to the human output voltage and the like of the subsequent phase shift circuit shown in FIG. 30,

FIG. 33 is a circuit diagram showing a configuration of a phase shift circuit including a condenser microphone. FIG. 34 is a circuit diagram showing a configuration of a phase shift circuit including an LR circuit.

FIG. 35 is a circuit diagram showing another configuration of the phase shift circuit including the LR circuit,

FIG. 36 is a circuit diagram showing a configuration of an oscillator including a phase inversion circuit,

FIG. 37 is a circuit diagram showing another configuration of the oscillator including the phase inversion circuit,

FIG. 38 is a circuit diagram in which a portion necessary for the operation of the phase shift circuit in the configuration of the operational amplifier is extracted. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments to which the present invention is applied will be specifically described with reference to the drawings. [First embodiment]

FIG. 1 is a circuit diagram showing a configuration of an FM modulator according to a first embodiment to which the present invention is applied.

The FM modulator 1 shown in the figure includes two phase shift circuits 110 C and 30 C that perform a total of 360 ° phase shift at a predetermined frequency, and a phase shift circuit 30 C at the subsequent stage. And a feedback resistor 70 that feeds back the output of the first stage to the input side of the phase shift circuit 110 C of the preceding stage. The feedback resistor 70 has a finite resistance value from 0 Ω. These two phase shift circuits 110 C and 30 C and the return resistor 70 constitute an oscillator.

The FM modulator 1 shown in FIG. 1 is provided with a condenser microphone as described later, and FM-modulates the voice collected by the condenser microphone and outputs it.

Therefore, as shown in FIG. 1, for example, an amplifier 2 and an antenna 3 are connected after the FM modulator 1, and the output of the FM modulator 1 is amplified by the amplifier 2 and transmitted from the antenna 3 to the air. It would be an FM wireless microphone. In addition to the case where the signal is transmitted from the antenna 3 to the multiplex, the signal may be transmitted to the transmission line 400 via the transmission driver 4 as shown in FIG.

Before describing the details of the FM modulator 1 shown in FIG. 1, the basic operation of the oscillator will be described.

Fig. 3 shows a simplified investigation by replacing the condenser microphone 141-1 and capacitor 14-2 included in the FM modulator 1 shown in ¾1 ^ with a fixed capacitance 14 capacitor. 6 is a circuit diagram showing a configuration of a device 5. FIG. The oscillator 5 shown in the figure includes two phase shift circuits 10 C and 30 C that perform a total of 360 ° phase shift at a predetermined frequency, and outputs the output of the subsequent phase shift circuit 30 C in the preceding stage. And a feedback resistor 70 for feeding back to the input side of the phase shift circuit 10C.

The phase shift circuit 10 C at the preceding stage constituting the oscillator 5 shown in FIG. 3 is composed of an operational amplifier (operational amplifier) 12, which is a type of differential amplifier, and the phase of a signal input to the phase shift circuit 10 C. Is shifted by a predetermined amount, and the resistor 16 and the capacitor 14 input to the non-inverting input terminal of the operational amplifier 12 and the input terminal of the phase shift circuit 10 C and the inverting input terminal of the operational amplifier 12 It is configured to include a resistor 18 inserted and a resistor 20 inserted between the output terminal of the operational amplifier 12 and the inverting input terminal. When an AC signal is manually input to the phase shift circuit 10 C having such a configuration,

The voltage VC1 appearing at both ends of the capacity 14 is applied to the non-inverting human terminal of the step 12. Also, since there is no potential difference between the two input terminals of the operational amplifier 12, the potential of the inverting input terminal of the operational amplifier 12 is equal to the potential of the connection point between the resistor 16 and the capacitor 14. Therefore, the same voltage VR1 as the π¾ terminal voltage VR1 of the resistor 16 appears at both ends of the resistor 18.

Here, when the resistor 1 8 as the resistance of the resistor 2 0 are equal, these two resistors 1 8, 2 0 for the same current flows through the resistor 2 0 both ends _c moreover the voltage VR1 appears also show, The voltage VR1 appearing at both ends of these two resistors 18 and 20 has the same direction in vector. Therefore, considering the inverting input terminal (voltage V C1) of the operational amplifier 12 as a standard, as shown in FIG. 4, the sum of the voltage VR1 across the resistor 18 in a vector manner is the input voltage The output voltage Eo is obtained by vectorially subtracting the voltage VR1 of the resistor 20 from Ei. The relationship between the magnitude and the phase of the input / output voltage can be expressed by an isosceles triangle with the input voltage E i and the output voltage E o as the hypotenuse and the base as twice the voltage VR1. It can be seen that the amplitude is the same as the amplitude of the input signal regardless of the frequency, and the phase shift amount is represented by 01 shown in FIG.

The phase shift [nj path 30 C] of the subsequent stage constituting the generator 5 shown in FIG. 3 is input to an operational amplifier 32 which is a type of differential amplifier and to this phase shift I] path 30 C. And a resistor 36 to shift the phase of the input signal by a predetermined amount to the non-inverting input terminal of the operational amplifier 32, and the input terminal of the phase shift circuit 30C and the inverting power of the operational amplifier 32. A resistor 38 is inserted between the output terminal of the operational amplifier 32 and the inverted terminal, and a resistor 40 is inserted between the output terminal of the operational amplifier 32 and the inverted human terminal. The basic configuration of the phase shift circuit 30 C is the same as that of the preceding phase shift circuit 10 C, and the capacity 3 4 and the resistor 3 6 which constitute the CR circuit in the phase shift circuit 30 C are connected. The order of connection is opposite to the order of connection between the capacity 14 and the resistor 16 constituting the CR circuit in the phase shift circuit 10C.

Therefore, considering the relationship between the magnitude and phase of the input / output voltage, assuming that the voltage across the capacitor 34 is VC2 and the voltage across the resistor 36 is VR2, as shown in Fig. 5, the input voltage E i And the output voltage E o is defined as the hypotenuse, and the base of the power K VC2 can be represented by an isosceles triangle. It can be seen that the phase shift amount is represented by 02 shown in FIG.

In this way, the phase of each of the two phase shift circuits 10 C and 30 C is shifted by a predetermined amount, and the amount of phase shift is determined by the entire two phase shift circuits 10 C and 30 C at a predetermined frequency. A signal totaling 360 ° is output. In addition, the output of the subsequent phase shift circuit 30 C is fed back to the input side of the phase shift circuit 10 C via the feedback resistor 70, and the loop has been completed by setting the loop gain of the feedback loop to 1 or more. Sometimes a sine wave oscillation occurs at a frequency such that the sum of the phase shift views is 360 °. If the resistors 18 and 20 have the same resistance value and the resistors 38 and 40 have the same resistance value, the gains of the phase shift circuits 10 C and 30 C become 1, and furthermore, in the feedback loop, The loop gain will be less than 1 because some peaks will occur. For this reason, in order to make the loop gain 1 or more, it is necessary to make the resistance value of the resistance 20 larger than the resistance 18 or make the resistance value of the resistance 40 larger than the resistance 38.

By the way, the FM modulator 1 shown in FIG. 1 has a configuration in which the phase shift circuit 10 C of the preceding stage included in the oscillator 5 described above is replaced with a phase shift circuit 110 C including a condenser microphone. Next, the FM modulator 1 having such a configuration will be described.c FIG. 6 is a circuit diagram showing the configuration of a phase shift circuit including a condenser microphone, and FIG. The configuration of the preceding phase shift circuit 110C included in the device 1 is shown. This phase-shift circuit 110 C is the same as the phase-shift circuit 10 C in the preceding stage included in the generator 5 shown in FIG. 3 except that a CR circuit comprising a resistor 16 and a capacitor 14 is connected to a resistor 16 and a capacitor microphone The right side shows the configuration in which a CR circuit consisting of 1 and 14 is replaced.

As described above, when the CR circuit is configured to include the condenser microphone 14-1, the time constant T (= CR) of the CR circuit slightly changes according to the capacitance of the condenser microphone 14-1. This change in capacitance reflects the change in sound pressure picked up by the condenser microphones 14-11, and the time constant of the CR circuit included in one phase shift circuit 110C changes according to the sound pressure. The frequency of the oscillation output also changes. In other words, FM-modulated signals can be easily obtained by using the condenser microphone 14-1 in the-part of the CR circuit. Therefore, the circuit configuration itself of the FM modulator 1 can be simplified. Further, each of the two phase shift circuits 110 C and 30 C constituting the FM modulator 1 is an all-pass circuit, and even if the frequency of the FM-modulated carrier is changed, the amplitude is changed. Is almost constant, and another configuration for preventing amplitude fluctuation is not required.

A general condenser microphone is a microphone that uses the change in capacitance of a parallel plate capacitor, applies a predetermined DC voltage between parallel electrodes through a resistance of several tens of Ω, and applies electrostatic capacitance due to sound pressure. The change in voltage according to the change in capacitance is extracted as an electrical signal. Therefore, it is necessary to apply a predetermined DC voltage for normal use, but in the present embodiment, the condenser microphone 1411 is used as a capacitor whose capacitance changes according to the sound pressure. Therefore, it is not necessary to apply a predetermined DC voltage.

Further, in the FM modulator 1 shown in FIG. 1, a condenser microphone is included in the preceding phase shift circuit, but a condenser microphone may be included in the subsequent phase shift circuit. That is, the phase shift circuit 30 C of the subsequent stage constituting the oscillator 5 shown in FIG. 3 is replaced with the phase shift circuit 130 C shown in FIG. 6 (B) (capacity signal in the phase shift circuit 30 C). (The one using condenser microphone 34-1 and capacity 34-2 instead of 4) may be used.

In the FM modulator 1 described above, the two phase shift circuits are both configured to include the CR circuit, but one of the phase shift circuits not including the condenser microphone is replaced with a phase shift circuit including the LR tol path. You can also.

FIG. 7 is a circuit diagram showing a configuration of a phase shift circuit 10L which can be replaced with the preceding phase shift circuit 10C included in the oscillator 5 shown in FIG. The phase shift circuit 10 L shown in FIG. 7 is different from the phase shift circuit 10 C shown in FIG. 3 in that a CR circuit consisting of the resistor 16 and the capacitor 14 is connected to the inductor 17 and the resistor 16. LR circuit. Considering the relationship between the magnitude and phase of the input / output voltage assuming that the voltage across the inductor 17 is VL1 and the voltage across the resistor 16 is VR1, as shown in Fig. 8, the input voltage E i and the output voltage E o Can be represented by an isosceles triangle whose base is twice the voltage VL1.The amplitude of the output signal is the same as the amplitude of the human-powered signal regardless of the frequency, and the amount of phase shift is shown in Fig. 8. It can be seen that it is represented by 03 as shown. If the time constant of the CR circuit in the phase shift circuit 10C shown in FIG. 3 and the time constant of the LR circuit in the phase shift circuit 10L shown in FIG. The transfer functions of the phase circuits 10C and 10L are both (1-Ts) / (1 + Ts). Here, s = jω.

Thus, the phase shift circuit 10L is equivalent to the phase shift circuit 10C, and the phase shift circuit 10C can be replaced with the phase shift circuit 10L. Therefore, in the oscillator 5 shown in FIG. 3, the phase shift circuit 10 C in the preceding stage is replaced with the phase shift circuit 10 L shown in FIG. 7, and the phase shift circuit 30 C in the latter stage is replaced by a condenser microphone. By replacing the phase shift | π | path 130 C shown in Fig. 6 (Β), each of the two phase shift circuits constitutes an FM modulator including an LR circuit or a CR circuit. Can be.

FIG. 9 is a circuit diagram showing a configuration of a phase shift circuit 30L that can be replaced with a subsequent phase shift circuit 30C included in the oscillator 5 shown in FIG. The phase shift circuit 30L shown in Fig. 9 is different from the phase shift circuit 30C shown in Fig. 3 in that the CRIHJ path consisting of the capacitor 34 and the resistor 36 is replaced by an LR circuit consisting of the resistor 36 and the inductor 37. It has a different configuration. Considering the relationship between the magnitude and phase of the human output voltage with the voltage across the resistor 36 as VR2 and the voltage across the inductor 37 as VL2, as shown in Fig. 10, the input voltage Ei and the output voltage Eo are The amplitude of the output signal is the same as the amplitude of the input ^ signal regardless of the frequency, and the position ffl shift is shown in Fig. 10. You can see that it is represented by 04. Assuming that the time constant of the CR circuit in the phase shift circuit 30C shown in FIG. 3 and the time constant of the LR circuit in the phase shift circuit 30L shown in FIG. The transfer functions of the circuits 30 C and 30 L are both 1 (1-T s) / (1 + T s).

As described above, the phase shift circuit 30L is equivalent to the phase shift circuit 30C, and the phase shift circuit 30C can be replaced with the phase shift circuit 30L. Therefore, in the generator 5 shown in FIG. 3, the subsequent phase shift circuit 30C is replaced with the phase shift circuit 30L shown in FIG. 9, and the preceding phase shift circuit 10C includes a condenser microphone. By substituting the phase shift circuit 110C shown in FIG. 6 (A), each of the two phase shift circuits can constitute an FM modulator including an LR line or a CR line.

[Second embodiment] In each phase shift circuit shown in Fig. 3, the output of the operational amplifier is directly fed back to the human side of the operational amplifier via a resistor.However, a voltage divider is connected to the output terminal of each operational amplifier to divide the voltage. The output may be fed back to the input side of the operational amplifier.

FIG. 11 is a circuit diagram showing a detailed configuration of an oscillator provided with a voltage dividing circuit in a phase shift circuit. The voltage dividing circuit composed of the resistors 21 and 23 is connected to the output terminal of the operational amplifier 12 in the phase shift M path 210C shown in FIG. It is connected to the anti-fc human input terminal of the operational amplifier 12 via the resistor 20. Similarly, the output terminal of the operational amplifier 32 in the phase shift circuit 230 C is connected to a voltage dividing circuit composed of the resistors 41 and 43, and the voltage dividing output terminal is connected to the operational amplifier via the resistor 40. 32 Connected to 2 inverting input terminal.

In Fig. 11, assuming that the resistance value of resistor 21 is R21 and the resistance value of resistor 23 is R23, the voltage dividing circuit consisting of the output voltage Eo of the operational amplifier 12 and the resistors 21 and 23 When R21 and R23 are sufficiently small with respect to the resistance value of the resistor 20, the relation of Eo = (1 + R21 / R23) Eo ' There is. Therefore, a gain greater than 1 can be obtained by adjusting the values of R21 and R23, and the vector diagram can be obtained by replacing the voltage Eo shown in Fig. 4 with the partial output Eo '. Even when the frequency changes, the & width of the output voltage E o is constant, and only the phase can be shifted by a predetermined amount. The same applies to the phase shift circuit 230 C. Even if the frequency changes, it is possible to shift only the phase by a predetermined fidelity while keeping the width of the output pressure E o constant. Thus, by providing a voltage dividing circuit in each of the two phase shift circuits, when the resistance values of the resistors 18 and 20 are the same and the resistance values of the resistors 38 and 40 are the same. Even if there is, the loop gain of the feedback loop formed by cascading the two phase shift circuits can be reliably set to 1 or more, and the oscillation operation can be stabilized. In addition, by configuring the capacity in the CR circuit of either of the two phase shift circuits 210 C and 230 C shown in FIG. 11 by using a condenser microphone, FIG. The FM modulator can be configured in the same manner as.

FIG. 11 shows an example in which a voltage dividing circuit is connected to the output terminals of the operational amplifiers 12 and 32 in the phase shift circuits 10 C and 30 C shown in FIG. A voltage divider is connected to the output terminals of the operational amplifiers in the phase shift circuits 10 L and 30 L shown in the figures and Fig. When the output terminal is fed back to the human side of each of the operational amplifiers 12 and 32, a stable oscillation operation similar to that of the oscillator 5A shown in FIG. 11 is performed.

[Third embodiment]

FIG. 12 is a circuit diagram showing another configuration of the oscillator. The oscillator 5B shown in the figure is configured to include two phase shift circuits 410C and 430C that perform a total of 360 ° phase shift at a predetermined frequency.

The oscillator 5A shown in Fig. 11 changes the frequency of the input AC signal by setting the resistances 倘 of the resistors 18 and 20 in the preceding phase shift circuit 10C to the same value. The amplitude change at the time of is suppressed. On the other hand, the phase shift circuit 4100 C in the preceding stage included in the oscillator 5 B shown in FIG. 12 does not have a shunt in the phase shift circuit and has a higher resistance than the resistance of the resistor 18 ′. By setting the resistance value of the resistor 20 'to a large value, the use of the phase shift circuit 410C is set to a value more unique than 1.

The same applies to the subsequent phase shift circuit 430C, and by setting the resistance value of the resistor 40 'to be larger than the resistance value of the resistor 38', the gain of the phase shift circuit 430C is set to 1 It is set to a larger value.

By the way, as described above, if the value of each resistor is set so that the gain of the phase shift circuit becomes a value more unique than 1, gain fluctuation may occur depending on the frequency of the input signal. For example, considering the preceding phase shift circuit 410C, when the frequency of the input signal is low, the phase shift circuit 410C becomes a voltage hollow path, and the gain at this time becomes 1 times. On the other hand, when the frequency is high, the phase shift circuit 4 10 (is an anti-amplifier, so the gain at this time is -m times (m is the resistance ratio between the resistance 20 'and the resistance 18'). When the frequency of the input signal changes, the gain of the phase shift circuit 410C also changes, and the amplitude of the output signal fluctuates.

Such amplitude fluctuation can be suppressed by connecting the resistor 19 to the inverting input terminal of the operational amplifier 12 and matching the gain when the frequency of the input signal is low with that when the frequency of the input signal is high. Specifically, assuming that the resistance of the resistor 18 'is r and the resistance of the resistor 20' is mr, the input signal is set by setting the resistance of the resistor 19 to mr / (m-1). When the frequency is 0 and infinity, the respective benefits of the phase shift 0 path 410C can be matched. Similarly, the phase shift circuit 4300C is also connected to the inverting input terminal of the operational amplifier 32. By connecting the resistor 39 having a predetermined resistance value, the amplitude fluctuation of the output signal can be suppressed. Note that one ends of the resistors 19 and 39 may be connected to a fixed potential other than the ground level.

In addition, the capacity in the CR iP] circuit, which is provided by either of the two phase shift circuits 41 C or 43 C shown in FIG. An FM modulator can be configured in the same manner as in the figure.

Although the oscillator 5B shown in FIG. 12 has a cascade connection of phase shift circuits 4110C and 4330C including a CR circuit, the CR circuit can be replaced with an LR circuit. _c For example, the phase shift circuit 4 10 L shown in FIG. 13 is the same as the previous phase shift circuit 4 10 C shown in FIG. 12, and the phase shift circuit 4 10 C is a phase shift circuit. It can be replaced with 410 L. Similarly, the phase shift circuit 430 L shown in FIG. 14 is equivalent to the phase shift circuit 430 C of the subsequent stage shown in FIG. It can be replaced by 30 L. When replacing the preceding phase shift circuit 4100C shown in FIG. 12 with the phase shift circuit 410L shown in FIG. 13, the subsequent phase shift circuit 43 shown in FIG. The capacity 34 in 0 C may be configured using a condenser microphone.

(Fourth embodiment)

In the FM modulator shown in Fig. 1, the combined phase shift of the two phase shift circuits is set to 360 ° at a predetermined frequency, but the two phase shift circuits are cascaded. The FM modulator may be configured by connecting a non-inverting circuit that does not change the phase to a part of the feedback loop formed as described above.

FIG. 15 is a circuit diagram showing a detailed configuration of a fourth embodiment of the FM modulator. The FM modulator 1A shown in the figure is the same as the FM modulator 1 shown in FIG. 1 in that the phase shift circuit 110C and the phase shift circuit 30C are connected in cascade, and the subsequent phase shifter is used. FIG. 1 shows that the non-inverting circuit 50 is connected to the output side of the circuit 30 C. FIG.

The non-inverting circuit 50 includes an operational amplifier 52 and resistors 54 and 56, and has a predetermined gain according to a resistance ratio of the two resistors 54 and 56. Therefore, the loss at the time of forming the closed loop can be compensated by this gain, and the loop gain of the feedback loop can be easily set to 1 or more. In addition, the non-inverting path 5 It is also possible for 0 to have a function as a power amplification stage.

In FIG. 15, as an example, the configuration in which the non-inverting circuit 50 is connected to the FM modulator 1 shown in FIG. 1 has been described, but the above-described various phase shift circuits are cascaded in an arbitrary order. The non-inverting circuit 50 shown in FIG. 15 may be connected to various FM modulators configured as described above.

(Fifth embodiment)

In the various FM modulators described above, the phase shift amount is controlled by two phase shift circuits, and the operation of adjusting the frequency at which the juice becomes 360 ° is performed.However, a phase inversion circuit is provided in a closed loop. By closing the aperture, the total amount of phase shift by the two phase shift circuits is 180. The vibration operation may be performed at a frequency such that:

FIG. 16 shows an In] path of an oscillator configured by cascading two phase shift circuits and a phase inversion Lnj path. The oscillator 5C shown in the figure is composed of a cascade connection of two stages of the preceding phase shift circuit 10C in the generator 5 shown in FIG. 3, and an operational amplifier 82 and resistors 84, 8 A phase inversion circuit 80 composed of 6 is connected, and the output of the phase inversion circuit 80 is fed back to the human-powered side of the preceding phase shift circuit 10 C via a resistance 70. Since 反 is inverted by the phase reversal fc0 path 80, when the phase shift amount 2 · by the two phase shift circuits 10 C becomes 180 °, the phase shift when the circuit goes through a closed loop Is 360 °, and a predetermined oscillation operation is performed by setting the loop gain of the loop at this time to 1 or more.

Therefore, by replacing one of the two phase shift circuits 10 C included in the oscillator 5 C with the phase shift circuit 110 C shown in the sixth f¾ | It is possible to construct an FM modulator using the sound that has been sounded; i ′ for the FM modulation signal. Alternatively, one of the two phase shift circuits 10 C included in the oscillator 5 C is replaced with the phase shift circuit 110 C shown in FIG. 6 (A), and the other is shifted as shown in FIG. The FM modulator may be configured in place of the circuit 10L.

(Sixth embodiment)

Although the oscillator 5C shown in FIG. 16 shows an example in which the phase shift circuit 10C is cascaded, the oscillator 5C shown in FIG. 3 may be cascaded with the subsequent phase shift circuit 30C.

FIG. 17 is a circuit diagram showing another configuration of the oscillator including the phase inversion IHJ path therein. In the oscillator 5D shown in FIG. 3, a phase shift circuit 30C at the subsequent stage in the oscillator 5 shown in FIG. 3 is vertically connected by two stages, and a phase inverting circuit 80 is connected to the subsequent stage. The output of the inversion circuit 80 is fed back to the human side of the preceding phase shift circuit 30 C via the feedback resistor 70.

Since the signal is inverted by the phase inverting circuit 80, when the total phase shift amount of the two phase shift circuits 30 C is 180 °, the phase shift amount when making a round of the closed loop is 3 60 °, and a predetermined oscillation operation is performed by setting the loop gain of the feedback loop at this time to 1 or more.

Therefore, by replacing one of the two phase-shift circuits 30 C included in the oscillator 5 D with the phase-shift circuit 130 C shown in FIG. 6B, sound is collected by the condenser microphone. It is possible to configure an FM modulator using the converted voice for the FM modulation signal. Alternatively, one of the two phase shift circuits 30 C included in the oscillator 5 B is replaced with a phase shift circuit 130 C shown in FIG. 6B and the other is shown in FIG. The FM modulator may be configured by replacing the phase shift circuit with 30 L.

(Seventh embodiment)

FIG. 18 is a circuit diagram showing a detailed configuration of the seventh embodiment of the FM modulator. The FM modulator 1B shown in the figure includes two phase shift circuits 710C and 630C that perform a total of 360 ° phase shift at a predetermined frequency, and a phase shift circuit 6 in the subsequent stage. A non-inverting circuit 650 that amplifies and outputs the output of the 3 0 C at a predetermined amplification level without changing the phase, and the output of the non-inverting circuit 65 0 is the input side of the previous phase shift circuit 7 10 C And a resistor 670 that feeds back the current. This resistor 670 has a finite resistance value from 0 Ω. The capacitor 672 connected in series with the resistor 670 is for blocking DC current, and its impedance is extremely small at the operating frequency, that is, it has a large capacitance. I have.

The FM modulator 1B is configured to include a condenser microphone (details will be described later), and uses the sound obtained by the condenser microphone as an FM modulation signal, and outputs an FM-modulated signal as an oscillation output. ing.

For example, as shown in Fig. 18, an amplifier 2 and an antenna 3 are connected after the FM modulator 1B, and the output of the FM modulator 6 is amplified by the amplifier 2 and the antenna If you send it out of the air from 3, it becomes an FM wireless microphone. In addition to transmitting the signal from the antenna 3 to the air, the signal may be transmitted to the transmission line 400 via the transmitting driver 4 as shown in FIG.

As in the case of the first embodiment, before describing the details of the FM modulator 1B shown in FIG. 18, the basic operation of the oscillator will be described.

Fig. 19 shows the case where the condenser microphone 614-1 and the capacitor 614-2 included in the FM modulator 1B shown in Fig. 18 are replaced with a fixed capacitance 614. FIG. 3 is a circuit diagram showing a configuration of the vibrator. The oscillator 5E shown in FIG. 3 has two phase shift circuits 6 10C and 630C that perform a phase shift of 360 ° by a total at a predetermined frequency, and the phase of the output signal of the subsequent phase shift circuit 630C. And a resistor 670 that feeds back the output of the non-inverting circuit 650 to the input side of the previous phase shift circuit 6100C. ing. The phase shift circuit 6100C in the preceding stage constituting the oscillator 5E shown in FIG. 19 is composed of a FET 612 connected to the input terminal of the phase shift circuit 610C, A capacitor 6 14 and a resistor 6 16 connected in series between the source 2 and the drain; a resistor 6 18 connected between the drain of the FET 6 12 and the positive power supply; and a FET 6 1 and a resistor 620 connected between the source and ground. The resistor 626 in the phase shift circuit 610 C is for applying an appropriate bias voltage to the FET 612. In addition, at least the FET 612 and the FET 632 described later may be replaced with a bipolar transistor.

Here, the resistance values of the two resistors 620 and 618 connected to the source and the drain of the FET 612 described above are set to be substantially equal, and the resistance of the input voltage applied to the gate is reduced to the AC component. In other words, a signal with the same phase is output from the source of the FET 612, and a signal whose phase is inverted and whose amplitude is equal to the signal output from the source is output from the drain of the FET 612. The amplitude of the AC voltage applied to the source and drain is Ei.

A series circuit (CR circuit) composed of a capacitor 614 and a resistor 616 is connected between the source and drain of the FET 612, and the voltage appearing at the source and drain of the FET 612 It's resistance 61 6 or capacity evening 6 1 The signal synthesized via 4 is output from the phase shift circuit 6100C.

By the way, the voltage VC1 appearing at both ends of the capacitor 614 and the voltage VR1 appearing at both ends of the resistor 616 are 90 ° out of phase with each other. Since it is equal to the voltage 2 Ei between the source and the drain of 2, as shown in Fig. 20, twice the voltage Ei is the hypotenuse, and the voltage VC1 across the capacitor 614 and the voltage VR1 across the resistor 616 are : A right triangle that forms the two intersecting sides will be formed. Assuming that the potential difference between the connection point of the capacitor 6 14 and the resistor 6 16 and the ground level is taken out as the output voltage Eo, this output voltage Eo starts from the center point of the semicircle shown in FIG. It can be represented by a vector ending at a point on the circumference where the voltage VC1 and the tortuosity pressure VR1 intersect.The amplitude of the output signal is constant regardless of the frequency, and the amount of phase shift is It can be seen that it is represented by 5 shown in Fig. 20.

Further, the phase shift circuit 630C of the subsequent stage constituting the oscillator 5E shown in FIG. 19 includes a FET 632 whose gate is connected to the input terminal of the phase shift circuit 630C, and a source ドレイン drain of the FET 632. A resistor 636 and a capacitor 634 connected in series, a resistor 638 connected between the drain of the FET 632 and the positive power supply, and a resistor connected between the source of the FET 632 and ground. 640. The resistor 646 in the phase shift circuit 630 C is for applying an appropriate bias voltage to the FET 632, and the capacitor 648 inserted between the phase shift circuits 630 C and 6100 C is. The current is ffl.

This phase shift circuit 630C has the same basic configuration as that of the previous phase shift circuit 610C, and connects the CR circuit composed of the resistor 636 and the capacitor 634 in the preceding phase shift circuit 610C. The difference is that it is opposite to the connection of the CR circuit consisting of the capacity 6 14 and the fan 6 6.

Therefore, considering the phase relationship between the terminal voltage of the resistor 636 as VR2 and the voltage across the capacitor 634 as V C2, as shown in Fig. 21, as shown in Fig. 21, the oblique side is twice the overvoltage Ei, | {The terminal voltage VR2 and the voltage VC2 across the capacitor 634 form a right-angled triangle that forms two orthogonal sides. Extract the difference between the ground point and the connection point of the resistor 636 and the capacitor 634 as the output voltage Eo In this case, the output voltage E o is represented by a vector whose starting point is the center point of the semicircle shown in Fig. 21 and whose end point is a point on the circumference where voltage VR2 and voltage VC2 intersect. It can be seen that the amplitude of the output signal is constant irrespective of the frequency, and the amount of phase shift is represented by 06 shown in FIG.

In this way, the phase is shifted by a predetermined amount at each of the two phase shift circuits 61 0 C and 63 0 C, and the two phase shift circuits 61 0 C and 63 0 C are shifted at a predetermined frequency. A signal in which the sum of the phase shift amounts to 360 ° is output by the whole.

The non-inverting circuit 650 shown in Fig. 19 has a resistor 654 connected between the drain and the power supply, and a FET 65 connected between the source and ground. 2, transistor 658 with base connected to the drain of FET 652 and collector connected to the source via resistor 660, and appropriate bias voltage applied to FET 652 And a resistor 6 62. The capacitor 664 provided in the preceding stage of the non-inverting circuit 650 shown in FIG. 19 is used to remove the DC component from the output of the subsequent phase shifting circuit 630 C. And only the AC component is manually input to the non-inverting circuit 650.

When the AC β 2 is input to the gate, the F ET 652 outputs an opposite-phase ^ sign from the drain. Also, when the opposite phase ^ is input to the base of the transistor 658, the phase of the signal further inverted, that is, the phase of the signal input to the gate of the FEΤ652 becomes in-phase. Is output from the collector, and this in-phase signal is output from the non-inverting circuit 650. The output of the non-inverting circuit 650 is taken out from the output terminal 92 as the output of the oscillator 510, and is fed back to the input side of the preceding phase shift circuit 610C via the resistor 670. I have.

The amplification of the above-described non-inverting circuit 650 is determined by the resistance values of the above-described resistors 654, 656, and 660. By adjusting the resistance values of these resistors, the amplification degree of FIG. The loop gain of the feedback loop formed by including the two phase shift circuits 61 0 C and 63 0 C and the resistor 67 0 shown in Fig. 10 can be set to 1 or more h. _c total bet amount sinusoidal oscillation is performed at a frequency such that the 3 6 0 ° Incidentally, FM modulation So匿1 B shown in the first 8 figures, J: the predicate was Hatsusuji device 5 E The included phase shift circuit 610 C of the previous stage is placed in the phase shift circuit 710 C including the condenser microphone. Next, the FM modulator 1B having such a configuration will be described.

FIG. 22 is a circuit diagram showing a configuration of a phase shift circuit including a condenser microphone. FIG. 22 (A) shows a configuration of a preceding phase shift circuit 710C included in the FM modulator 1B. I have. This phase shift circuit 710C is a capacitor microphone which is composed of a capacitor circuit 614 and a resistor 616 in the former stage phase shift circuit 610C included in the oscillator 5E shown in FIG. It has a configuration in which it is replaced with a CR circuit consisting of 614-1 and capacity 614-2 and resistor 616.

Thus, when a CR circuit including the condenser microphone 614-1 is formed, the time constant T (= CR) of the CR circuit varies slightly according to the static capacity of the condenser microphone 614-1. I do. This change in the electrostatic landscape reflects the change in the rising sound pressure of the condenser microphone 6114, and the time constant of the CR circuit included in one of the phase shift circuits 7 10 C according to the sound pressure changes. Because of the change, the frequency of the oscillation output also changes. In other words, by using the condenser microphone 614-1 as a part of the CR circuit, FM-modulated signals can be easily obtained.

In the FM modulator 1B shown in FIG. 18, a condenser microphone is not provided in the preceding phase shift circuit, but a condenser microphone may be included in the subsequent phase shift circuit. That is, the phase shift circuit 630 C of the subsequent stage constituting the oscillator 5 E shown in FIG. 19 is replaced with the phase shift circuit 730 C shown in FIG. 22 (Β) instead of the capacitor 634 in the phase shift circuit 630 C. The condenser microphone 634-1 and the capacity 634-2 may be replaced by rivers.

In the above-described FM modulator 1, the two phase shift circuits are both configured to include the CR circuit, but one of the phase shift circuits that does not include the condenser microphone can be replaced with a phase shift circuit that includes an LR circuit. .

For example, FIG. 23 is a circuit diagram showing a configuration of a phase shift circuit 610 L that can be replaced with the preceding phase shift circuit 610 C included in the generator & generator 5 shown in FIG. The phase shift circuit 610 L shown in FIG. 23 is a CR circuit consisting of the capacitor 614 and the resistor 616 in the phase shift circuit 610 C shown in FIG. It has a configuration in which it is replaced with an LR circuit consisting of an inductor 617. Connect the voltage across resistor 6 16 to VR1, Assuming that the pressure at both ends of the inductor 6 17 is VL1, as shown in FIG. 24, the oblique side is twice the voltage E i, the r end of the resistor 6 16 ^ pressure VR1 and both ends of the inductor 6 17 The voltage VL1 forms a quotient triangle forming two sides that are orthogonal to each other. Assuming that the potential difference between the connection point between the resistor 6 16 and the inductor 6 17 and the ground level is taken out as the output voltage E o, this output voltage E o is the center of the half circle shown in Fig. 24. It can be expressed as a vector with the point as the starting point and the end point at the-point of the circumference I: where the voltage VR1 and the voltage VL1 intersect. The amplitude of the output signal is constant regardless of the frequency, and the phase shift It can be seen that the data amount is represented by 07 shown in FIG.

By the way, assuming that the time constant of the CR circuit of the phase shift circuit 6 10 C 內 shown in FIG. 19 and the time constant of the LR circuit in the phase shift circuit 6 10 L shown in FIG. The transfer functions of these phase shift circuits 6110C and 610L are both a (1−Ts) / (1 + Ts). Here, s = jw, and a is the gain of each phase shift circuit.

As described above, the phase shift circuit 610L is equivalent to the phase shift circuit 610C, and replacing the phase shift circuit 610C with the phase shift circuit 610L is an ": I function." Therefore, in the oscillator 5E shown in FIG. 19, the phase shift circuit 6100 of the preceding stage is replaced with the phase shift circuit 6100L shown in FIG. By replacing 0 C with the phase shift circuit 730 C shown in Fig. 22 (B) that includes a capacitor mark, each of the two phase shift circuits becomes LR | An FM modulator including the IiiJ path can be configured.

FIG. 25 is a circuit diagram showing a configuration of a phase shift circuit 630 L which can be replaced with a subsequent phase shift circuit 630 C included in the oscillator 5 E shown in FIG. The phase shift circuit 63 0 L shown in Fig. 25 is connected to the CR circuit consisting of the resistor 6 36 and the capacitor 63 4 in the phase shift circuit 63 0 C shown in Fig. It has a configuration in which it is replaced with an LR circuit consisting of 3 7 and resistor 6 3 6. Assuming that the voltage between both ends of the inductor 6 3 7 is VL2 and the voltage between both ends of the resistor 6 3 6 is VR2, as shown in Fig. 26, twice the voltage E i is the hypotenuse, and the voltage across the inductor 6 3 7 is VL2 and the voltage VR2 across the resistor 636 form a right-angled rectangle that forms two orthogonal sides. Assuming that the potential difference between the connection point between the inductor 637 and the resistor 636 and the ground level is taken out as the output voltage Eo, this output voltage /: HEo is the center point of the semicircle shown in Fig. 26. To It can be represented by a vector with the start point as the end point of the circumference h where the voltage V L2 and the voltage V R2 intersect.The amplitude of the output signal is constant regardless of the frequency, and the phase shift It can be seen that M is represented by 08 shown in FIG.

By the way, assuming that the time constant of the CR circuit in the phase shift circuit 63 0 C shown in FIG. 19 and the time constant of the LR circuit in the phase shift circuit 63 0 L shown in FIG. The transfer functions of these phase shift circuits 63 0 C and 63 0 L are both 1 a (1-T s) / (1 + T s).

As described above, the phase shift circuit 630L is equivalent to the phase shift circuit 630C, and the phase shift circuit 630C can be replaced with the phase shift circuit 630L. Therefore, in the oscillator 5E shown in FIG. 19, the subsequent phase shift circuit 63 0 C is replaced with the phase shift circuit 63 0 L shown in FIG. By replacing 0 C with the phase shift circuit 710 C shown in Fig. 22 (A), which includes a capacitor microphone, each of the two shift circuits includes an LR circuit or a CR circuit. An FM modulator can be configured.

[Eighth Embodiment]

In the various types of FM modulator described in the seventh embodiment described above, the oscillation operation is performed at a wave number where the total phase shift amount of the two phase-shifted zero paths is 360 °. By connecting a phase inversion circuit to the closed loop, the oscillation operation may be performed at a frequency at which the sum of the phase shift views by the two phase shift circuits is 180 °.

FIG. 27 is a circuit diagram of an oscillator configured using two phase shift circuits and a phase inversion circuit. The oscillator 5F shown in the figure is composed of a cascade connection of two stages of the phase shift circuit 610C at the preceding stage in the oscillator 5 1 shown in Fig. 19, and the FET 682 and the resistor 6884 and A phase inverting circuit 680 consisting of 686 is connected, and the output of the phase inverting circuit 680 is fed back to the human side of the previous stage via the resistor 670 through the phase shifter [J path 610 C]. You.

Since the signal is inverted by the phase inversion circuit 680, when the total phase shift amount of the two phase shift circuits 610C is 180 °, the phase shift when the circuit goes through a closed loop is completed. In this case, the feedback amount becomes 360 °, and the loop gain of the feedback loop at this time * 1 By setting, a predetermined swing operation is performed.

Therefore, by replacing one of the two phase shift circuits 6 10 C included in the oscillator 5 F with the phase shift circuit 7 10 C shown in FIG. 22 (A), the sound was collected by the condenser microphone. It is possible to configure an FM modulator using sound ^ for an FM modulation signal. Alternatively, one of the two phase shift circuits 6 10 C included in the oscillator 5 F is replaced with the phase shift circuit 7 10 C shown in FIG. 22 (A), and the other is replaced with the phase shift circuit 7 10 C shown in FIG. The FM modulator may be configured in place of the phase shift path 6101L shown.

(Ninth embodiment)

FIG. 28 is a circuit diagram of another oscillator configured by cascade-connecting two phase shift circuits and a phase inversion circuit. The oscillator 5G shown in the figure has a two-stage cascade connection of the subsequent phase shift circuit 63 0 C in the oscillator 5 E shown in FIG. 19, and a phase inversion circuit 680 connected to the subsequent stage. Then, the output of the phase inversion circuit 680 is fed back to the input side of the preceding phase shift circuit 630 C via the resistor 670.

Since the signal is inverted by the phase shift circuit 680, when the total phase shift amount of the two phase shift circuits 63 ° C reaches 180 °, the phase shift when the circuit goes through a closed loop is completed. 3600. A predetermined oscillation operation is performed by setting the loop gain of the feedback loop at this time to 1 or less.

Therefore, by replacing one of the two phase-shift circuits 630C included in the oscillator 5G with the phase-shift circuit 730C shown in FIG. 22 (B), the sound collected by the condenser microphone can be obtained. This makes it possible to configure an FM modulator using the FM modulation signal. Alternatively, one of the two phase shift circuits 630C included in the oscillator 5G is replaced with a phase shift circuit 730C shown in FIG. 22 (B), and the other is replaced with the phase shift circuit shown in FIG. The FM modulator may be configured by replacing the phase shift circuit 630 L shown in FIG.

Embodiment of i10)

FIG. 29 is a circuit diagram showing the detailed configuration of the tenth embodiment of the FM modulator _c . The FM modulator 1C shown in FIG. 29 does not change the phase of the input AC signal. Performs a total of 360 ° phase shift at the specified frequency with the non-inverting circuit 850 output It is configured to include two phase shift circuits 910C and 830C, and a feedback resistor 870.

The non-inverting circuit 850 functions as a buffer circuit, and includes, for example, an emitter follower circuit, a source follower circuit, and the like. When the element constant of each element such as the feedback resistor 870 is selected so as to minimize the loss and the like when directly connected, the non-inverting circuit 850 is omitted and the FM modulator is omitted. 1 C may be configured.

The FM modulator 1C shown in the 29th is configured to include a condenser microphone (details will be described later), and FM-modulates the sound collected by the condenser microphone and outputs it.

For example, as shown in Fig. 29, amplifier 2 and antenna 3 are connected after FM modulator 1C, and the output of FM modulator 1 is amplified by amplifier 2 and sent out from antenna 3 to the air. It would be an FM wireless microphone. In addition to transmitting the signal from the antenna 3 to the air, the signal may be transmitted to the transmission line 400 via the transmitting driver 4 as shown in FIG.

Before describing the details of the FM modulator 1C shown in FIG. 29, the basic operation of the generator will be described.

FIG. 30 shows the condenser microphone 8 14-1 and the capacity 8 1 4-2 included in the FM modulator i¾: 1 C shown in FIG. FIG. 3 is a circuit diagram showing a configuration of an oscillator 5H simplified in place of FIG.

The phase shift circuit 810C at the front stage shown in the figure includes a differential amplifier 812 that amplifies the differential voltage of the two inputs with a predetermined amplification and outputs the amplified signal, and a phase II that converts the phase of the input AC signal to a predetermined II. The capacitor 814 and the resistor 816 which are shifted to the non-inverting input terminal of the differential amplifier 812 and the voltage level of about 1 Z2 without changing the phase of the input AC signal. And a resistor 818 and 820 which are input to the inverting input terminal of the differential amplifier 812.

FIG. 31 is a vector diagram showing the relationship between the input / output voltage of the phase shift circuit 8100 C shown in FIG. 30 and the voltage appearing in the capacity and the like.

As shown in the figure, the voltage VR1 appearing across the resistor 8 16 and the voltage The voltage VC1 appearing at both ends is 90 ° out of phase with each other, and the vector sum of these is equivalent to the input voltage Ei of the phase shift circuit 8100C. Accordingly, when the amplitude of the input voltage Ei is constant and only the frequency changes, the voltage VR1 across the resistor 8 16 and the voltage VC1 across the capacitor 8 14 along the circumference of the semicircle shown in FIG. Changes.

In addition, the voltage applied to the non-inverting input terminal of the differential amplifier 812 (the voltage VC1 across the capacitor 814) to the voltage applied to the inverting input terminal (the voltage Ei / 2 across the resistor 820) is calculated. The difference obtained by the torque is the difference voltage Eo '. This differential voltage Eo 'can be represented by a vector whose center point is the starting point and whose end point is a point on the circumference where voltage VC1 and voltage VR1 intersect in the semicircle shown in Fig. 31. And its size is equal to the radius of the semicircle Ei / 2.

The output voltage Eo of the differential amplifier 812 is obtained by amplifying the differential voltage Eo ′ with a predetermined amplification factor. Therefore, the above-described phase shift circuit 8100C operates as an all-pass circuit, in which the output voltage Eo is constant regardless of the frequency of the input voltage Ei. Further, as is clear from FIG. 31, since the voltage VC1 and the voltage VR1 intersect at right angles on the circumference, the phase difference between the input pressure Ei and the voltage VC1 varies from a frequency ω of 0 to ∞. From 90 ° in the clockwise direction (phase lag direction) based on the human-power voltage Ei. To change. Then, the phase shift amount 09 of the entire phase shift circuit 8 10 C changes from 0 ° to 180 ° according to the frequency.

Similarly, the subsequent phase shift circuit 830C shown in FIG. 30 includes a differential amplifier 832 that amplifies the differential voltage of the two inputs with a predetermined amplification and outputs the amplified voltage, and shifts the phase of the input AC signal by a predetermined amount. And a capacitor 834 and a resistor 836 that are input to the non-inverting input terminal of the differential amplifier 832, and the voltage level is divided into about 1/2 without changing the phase of the input AC signal, and the differential amplifier is divided. It is configured to include resistors 838 and 840 input to the inverting input terminal of 812.

FIG. 32 is a vector diagram showing the relationship between the input / output voltage of the phase shift circuit 830C shown in FIG. 30 and the voltage appearing in the capacity and the like.

As shown in the figure, the voltage VC2 appearing at both ends of the capacitor 834 and the voltage VR2 appearing at both ends of the resistor 836 are out of phase with each other by 90 °. Is the input voltage E i. Therefore, when the amplitude of the input signal is constant and only the frequency changes, the voltage VC2 across the capacitor 834 and the voltage VR2 across the resistor 836 along the circumference of the semicircle shown in FIG. Changes.

Also, the voltage applied to the non-inverting input terminal of the differential amplifier 832 (the voltage VR2 across the resistor 836) and the voltage applied to the inverting input terminal (the voltage E i / 2 ) Is the difference voltage E o '. This difference voltage E o 'is represented by a vector whose center point is the start point and whose end point is a point on the circumference where voltage VR2 and voltage VC2 intersect in the semicircle shown in Fig. 32. Whose size is equal to the radius of the semicircle E i / 2.

The output voltage E o of the differential amplifier 832 is obtained by amplifying the difference voltage E o 'with a predetermined amplification factor. Therefore, the above-described phase shift circuit 830C operates as an all-pass circuit, since the output voltage E o is constant regardless of the frequency of the input signal.

Further, as is clear from FIG. 32, since the voltage H: VR2 and the voltage VC2 intersect at right angles on the circumference, the phase difference between the input voltage Ei and the voltage VR2 is 180 as it changes. To 270 °. Then, the phase shift amount 010 of the entire phase shift circuit 830C changes from 180 ° to 360 ° according to the frequency. In this way, the phase is shifted by a predetermined amount at each of the two phase shift circuits 8100C and 8300C, and the two phase shift circuits 8100C and 8300C are shifted at a predetermined frequency. A signal is output in which the sum of the phase shifts -M is 360 °.

By the way, the FM modulator 1 C shown in FIG. 29 includes a phase shift circuit 8 10 C in the preceding stage included in the oscillator 5 H shown in FIG. Next, the FM modulator 6 having such a configuration will be described.

FIG. 33 is a circuit diagram showing a configuration of a phase shift circuit including a condenser microphone. FIG. 33A shows a configuration of a phase shift circuit 910C of a preceding stage included in the FM modulator 1C. It is shown. This phase shift circuit 910C is a CR circuit comprising a capacitor 814 and a resistor 816 in the previous phase shift circuit 8100C included in the oscillator 5H shown in FIG. Is replaced by a CR circuit consisting of a condenser microphone 8 14-1 and a capacitor 8 14-2 and a resistor 8 16. In this way, when a CR circuit is configured to include the condenser microphone 814-1, the time constant T (= CR) of this CR circuit is equal to the capacitance of the condenser microphone 814-1. It changes minutely in response. This change in capacitance reflects the change in sound pressure picked up by the condenser microphone 814-1, and the time constant of the CR circuit included in the phase shift circuit 910C changes according to the sound pressure. Therefore, the frequency of the oscillation output also changes. That is, by using the condenser microphone 814-1 in the-part of the CR circuit, it is possible to easily obtain the FM-modulated β signal.

In the FM modulator 1C shown in FIG. 29, a condenser microphone is provided in the preceding phase shift circuit, but a condenser microphone may be included in the subsequent phase shift circuit. That is, the subsequent phase shift circuit 830 C constituting the oscillator 5 shown in FIG. 30 is connected to the phase shift circuit 930 C shown in FIG. 3311 (Β) (the capacity of the capacitor 834 in the phase shift circuit 830 C). Alternatively, a condenser microphone 834-1 and a capacitor 834-2 may be used.

Although the above-mentioned FM modulator 1C has the two phase shift circuits both including the CR circuit, it is also possible to replace the phase shift circuit not including the condenser microphone with the LR [phase shift circuit including the port I path]. it can.

For example, FIG. 34 is a circuit diagram showing a configuration of a phase shift circuit 8110L replaceable with the preceding phase shift circuit 8100C included in the oscillator 5 shown in FIG. The phase shift circuit 810 L shown in FIG. 34 is different from the phase shift circuit 810 C shown in FIG. 30 in that a CR circuit consisting of a capacitor 814 and a resistor 8 16 The configuration is such that it is replaced with an LR circuit consisting of an inductor 8 17.

By the way, assuming that the time constant of the CR circuit in the phase shift circuit 810C shown in FIG. 30 and the time constant of the LR circuit in the phase shift circuit 810L shown in FIG. The transfer functions of the phase circuits 810C and 810L are both a (1—Ts) / (1 + Ts). Here, s = jw, and a is the gain of each phase shift circuit.

As described above, the phase shift circuit 8101L is equivalent to the phase shift circuit 8110C, and the phase shift circuit 810C can be replaced with the phase shift circuit 8101L. Therefore, in the oscillator 5H shown in FIG. 30, the phase shift circuit 810C in the preceding stage is replaced with the phase shift circuit 810C shown in FIG. By replacing the phase shift circuit 930C shown in Fig. 33 (B), which includes the phase shifter, each of the two phase shift circuits can constitute an FM modulator including an LR circuit or a CR circuit. it can.

FIG. 35 is a circuit diagram for reducing the configuration of the phase shift circuit 830 L which can be replaced with the subsequent phase shift circuit 830 C included in the oscillator 5 H shown in FIG. The phase shift circuit 830 L shown in FIG. 35 is different from the phase shift circuit 830 C shown in FIG. 30 in that a CR circuit consisting of a resistor 836 and a capacitor 834 is connected to the inductor circuit. It has a configuration in which it is replaced by an LR circuit consisting of 837 and a resistor 836.

By the way, the time constant of the CR circuit in the phase shift circuit 830 C shown in FIG. 30 and the time constant of the LR circuit in the phase shift circuit 830 L shown in FIG. Then, the transfer functions of these phase shift circuits 830C and 830L are both -a (1-Ts) / (1 + Ts).

Thus, the phase shift circuit 830 L is equivalent to the phase shift circuit 830 C, and it is possible to replace the phase shift circuit 830 C with the phase shift circuit 830 L. Therefore, in the oscillator 5H shown in FIG. 30, the subsequent phase shift circuit 830C is replaced with the phase shift circuit 830L shown in FIG. By replacing 0 C with the phase shift circuit 910 C shown in Fig. 33 (A) including a capacitor microphone, the phase shift circuit including the LR circuit and the phase shift circuit including the CR circuit are connected vertically. This makes it possible to construct a modified FM modulation device.

[Eleventh embodiment]

In the FM modulator 1C shown in FIG. 29 described above, the oscillation operation is performed at a frequency at which the sum of the phase shifts by the two phase shift circuits becomes 360 °. By connecting a phase inversion circuit in the loop, the oscillation operation may be performed at a frequency at which the sum of the phase shift amounts of the two phase shift circuits is 180 °.

FIG. 36 is a circuit diagram showing a configuration of an oscillator configured using two phase shift circuits and a phase inversion circuit. The oscillator 5J shown in the figure has a phase inverting circuit 880 for inverting the phase of an input AC signal and outputting the inverted signal, and a total of 180 at a predetermined frequency. It is configured to include two phase shift circuits 8100 C for performing the phase shift of the above and a feedback resistor 870. The phase relationship between the input and output signals of the two phase shift circuits 8100C is as described with reference to FIG. 31. At a predetermined frequency, the phase shift by the entire two phase shift circuits 8100C is performed. The sum of fi is 180 °.

Further, a phase inversion circuit 880 connected in front of the two phase shift circuits 810C inverts the phase of the input AC signal. For example, an emitter ground circuit and a source ground _c Thus realized by a circuit that combines a circuit or an operational amplifier resistor, the phase inversion circuit 8 8 0 for the phase of the signal is inverted by the phase shift amount of the interleaf ten by two phase shifting circuits 8 1 0 C Is 180 °, the phase shift amount when the circuit goes through the closed loop becomes 360 °, and the specified oscillation operation is performed by setting the loop gain of the feedback loop to 1 or more at this time. .

Therefore, by replacing one of the two phase shift circuits 810C included in the oscillator 5J with the phase shift circuit 910C shown in the third fel (A), the signal is collected by the condenser microphone. It is possible to configure an FM modulator that uses the sound that has been emitted for the FM modulation signal. Alternatively, one of the two phase-shift circuits 8100C included in the oscillator 5J is replaced with the phase-shift circuit 9110C shown in FIG. 33 (A) [H] and the other is shifted to the third The FM modulator may be configured by replacing the phase shift circuit 8101L shown in FIG.

[First and second embodiments]

FIG. 37 is a circuit diagram of another oscillator configured using two phase shift circuits [nl path and phase inversion path]. The oscillator 5K shown in the same figure is connected in cascade using two phase shift circuits 830C at the subsequent stage in the oscillator 5H shown in FIG. A phase inversion circuit 880 is connected to the input side, and the output of the subsequent phase shift circuit 830C is fed back to the input side of the phase inversion circuit 880 via the feedback resistor 870.

Since the signal is inverted by the phase inverting circuit 880, when the total phase shift amount of the two phase shift circuits 830C is 180 °, the phase shift when the circuit goes through a closed loop is completed. 3600. By setting the loop gain of the feedback loop to 1 or more h at this time, a predetermined generating operation is performed.

Therefore, by replacing one of the two phase shift circuits 830C included in the oscillator 5K with the phase shift circuit 930C shown in FIG. It is possible to configure an FM modulator using the sound collected by the microphone as the FM modulation signal. Alternatively, one of the two phase shifters 830C included in the oscillator 5K is replaced with the phase shifter 930C shown in FIG. 33 (B), and the other is replaced with the one shown in FIG. The FM modulator may be configured by replacing the phase shift circuit 8

By the way, the oscillators 5 C, 5 D, 5 E, 5 F, 5 G, 5 H, 5 J, 5 K, etc., described above, are a non-inverting circuit and two phase shifting circuits or a phase inverting circuit and two phase shifting circuits. And a predetermined tuning operation by setting the total phase shift to 360 ° at a predetermined frequency by all three connected circuits. . Therefore, focusing only on the amount of phase shift, there is a certain degree of freedom as to which of the two phase shift circuits is used in the preceding stage or in which order the three circuits described above are connected. The connection order can be determined as needed.

[Other embodiments]

Note that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

For example, in each of the embodiments described above, the case where the condenser microphone and the capacitor are connected in series has been described. Therefore, the capacity connected to the condenser microphone in a row may be omitted, the condenser microphone and the capacity may be connected in parallel, or the condenser microphone and a plurality of capacity may be combined in parallel and in series. . Comparing the case where a condenser microphone is used alone and the case where a condenser microphone and a capacitor are connected in series or in parallel, or a combination of these, the capacitance of the connected capacitor is the latter. By changing the value, there is an advantage that the degree of change of the overall capacitance fi, that is, the FM modulation degree can be adjusted.

Also, in each of the above-described embodiments, the FM constants of the FM modulator iS with a fixed carrier frequency are realized by fixing the element constant of each element in each phase shift path. The frequency may be arbitrarily changed. For example, taking the FM modulator 1 shown in FIG. 1 as an example, the phase shift circuit 110 By changing at least one of 6, 6 and 6 with a variable resistor to vary this resistance value, or by changing at least one of the capacity 14-2 or 34 in the phase shift circuit 110 C or 30 C. By changing this capacitance by replacing it with a variable capacitance element, the frequency of the signal output from the FM modulator 1 can be changed by changing the amount of phase shift by each phase shift circuit. it can. More specifically, the above-described variable resistor can be formed by using a channel resistance of a FET whose gate voltage can be changed, and a reverse bias voltage for applying a variable capacitance element between an anode and a cathode can be used. Can be formed by a variable-capacitance diode whose gate capacitance can be changed, or by a FET whose gate capacitance can be changed by a gate voltage.

In particular, when the "J variable resistance" is formed by using the channel resistance of the FET, the p-channel FET and the n-channel FET are connected in parallel to form a single variable resistor, which reduces the nonlinearity of the FET. It is possible to improve the area and output a signal with less distortion with reduced harmonic components Similarly, when the LR circuit is included in the phase shift circuit, the inductor in the LR circuit Alternatively, the resistor may be configured using a variable inductor or a variable resistor.

In addition, I: In each of the various oscillators described above, a voltage divider is connected to the output side of the phase shifter at the subsequent stage, and the manpower of the circuit is extracted as the oscillation output, and the divided output is fed back to the feedback resistor. It may be connected to the input side of the preceding phase shift circuit via 0 or the like. By providing such a voltage dividing circuit, the oscillation β can be amplified with a predetermined amplification degree. Therefore, the amplifier 2 shown in FIG. 1 can be omitted, or the amplification degree of the amplifier 2 can be reduced.

In the first to sixth embodiments described above, high stability is realized by configuring an FM modulator using phase shift circuits 110 C, 30 C, etc. using operational amplifiers. However, when the phase shift circuit is used in 110 C, 30 C, etc., the offset voltage and the voltage gain are not required to be so high, so the differential with the specified gain is required. An amplifier may be used instead of the operational amplifier in the phase shift circuit.

FIG. 38 is a circuit diagram in which a part necessary for the operation of the phase shift circuit in the configuration of the operational amplifier is extracted, and the whole operates as a differential amplifier having a predetermined gain. In the figure The differential amplifier shown includes a differential input stage 100 composed of FETs, a constant current circuit 102 for supplying a constant current to the differential input stage 100, and a predetermined current supplied to the constant current circuit 102. It comprises a bias circuit 104 for applying a bias voltage and an output amplifier 106 connected to the differential input stage 100. As shown in the figure, the multistage amplifier circuit for gaining the voltage gain included in the actual operational amplifier is omitted, so that the configuration of the differential amplifier can be simplified and a wider band can be achieved. In this way, by simplifying the circuit, the upper limit of the operating frequency can be reduced to 0 °, and accordingly, the upper limit of the output frequency of the FM modulator configured using this differential amplifier is increased. can do. Availability on litter

A condenser microphone is installed in one of the two phase-shift circuits connected vertically, and the sound collected by the condenser microphone is directly FM-modulated and output, so that changes in the capacitance of the condenser microphone are converted to a voltage. This eliminates the need for additional circuits and the like, and can simplify the circuit configuration of the entire FM modulator.

Claims

The scope of the claims

1. Two phase-shift circuits of the all-pass type including a differential amplifier and a CR circuit are provided, and these two phase-shift circuits are cascaded to output the output of the latter-stage phase-shift circuit to the preceding-stage phase-shifter [Ml By using a condenser microphone as a capacitor in the CR circuit included in one of the two phase-shift circuits, the signal was FM-modulated from one of the two phase-shift circuits. A FM modulator characterized by outputting a signal.

2. At least one of the two phase-shift circuits includes a first resistor having a − / J terminal connected to the inverting input terminal of the differential amplifier and the other end connected to the CR circuit, A second resistor connected between the output terminal and the inverting input terminal of the amplifier; and an AC signal is manually input to the inverting input terminal of the differential amplifier via the first resistor. 2. The FM modulator according to claim 1, wherein a connection between the capacitor and the resistor in the CR circuit is connected to a non-inverting input terminal of the differential amplifier.

3. At least one of the two phase shift circuits includes a first resistor having a negative terminal connected to the inverting input terminal of the differential amplifier and the other terminal connected to the CR circuit, and the differential amplifier. And a second resistor connected between an output terminal of the voltage divider circuit and an inverting input terminal of the differential amplifier. An AC signal is input to the inverting input terminal of the self-differential amplifier via the resistor of Step 1, and the connection between the capacitor and the resistor in the CR iuJ path is connected to the non-inverting human terminal of the differential amplifier. The FM modulator according to claim 1, characterized in that:

4. At least one of the two phase shift circuits includes a first resistor having one end connected to an inverted human input terminal of the differential amplifier and the other end connected to a ^ CR circuit, and a differential resistor of the differential amplifier. A second resistor connected between the output terminal and the inverting input terminal; and a third resistor having one end connected to the inverting input terminal of the differential amplifier and the other end grounded, An AC signal is input to the inverting input terminal of the differential amplifier via the first resistor, and a connection between the capacitor and the resistor in the CR circuit is connected to a non-inverting input terminal of the differential amplifier. The FM modulator according to claim 1, wherein the FM modulator is characterized in that:

5. At least one of the two phase shift circuits indicates a voltage dividing circuit including first and second resistors having substantially equal resistance values, and a voltage dividing terminal of the output terminal of the voltage dividing circuit. Position to said Capacity evening and resistance characteristics to output is amplified by a predetermined amplification degree by the potential difference between the potential of the connection point before the differential amplifier in the CR ^circuit: determined in range囲第1 wherein FM modulator.

6. A non-inverting circuit that outputs the signal without changing its phase is connected to a part of a feedback loop formed by cascading the two phase shifting circuits,

2. The FM modulator according to claim 1, wherein the order of connection between the capacitor and the resistor in the CR circuit is reversed in the two phase shift circuits.

7. Connect a phase inversion circuit that inverts the phase of the signal and outputs it to a part of a feedback loop formed by cascading the two phase shift circuits,

2. The FM modulator according to claim 1, wherein the order of connection between the capacitor and the resistor in the CR circuit is the same in the two phase shift circuits.

8. At least one of the CR circuits includes a variable resistor or a variable capacitance element,

The FM modulator according to claim 1, wherein a carrier frequency of the FM-modulated signal is varied by changing a resistance value of the variable resistor or a capacitance of the variable capacitance element. .

9. An all-pass type first phase shift circuit including a differential amplifier and a CR circuit, and an all-pass type second phase shift circuit including a differential amplifier and an LR circuit. The second phase shift circuit is cascaded in a predetermined order, and the output of the subsequent phase shift circuit is fed back to the input side of the preceding phase shift circuit, and is included in the first phase shift circuit. An FM modulation device, comprising: outputting a FM-modulated signal from one of the first and second phase shift circuits by using a condenser microphone as a capacity in the CR circuit.

10. At least one of the first and second phase shift circuits has a first end connected to the inverting input terminal of the differential amplifier and a second end connected to the CR circuit or the LR circuit. And a second resistor connected between the output terminal and the non-input terminal of the differential amplifier, and the inverting input terminal of the differential amplifier via the first resistance. An AC signal is input to the differential amplifier, and the connection between the capacitor and the resistor in the CR circuit or the connection between the inductor and the resistor in the LR circuit is connected to the differential amplifier. 10. The FM modulator according to claim 9, wherein the FM modulator is connected to a non-inverting human input terminal f-.

At least one of the first and second phase shift circuits has a negative end connected to the inverting input terminal of the differential amplifier and a second end connected to the CR circuit or the LR circuit. A voltage divider connected to the output terminal of the differential amplifier; a second resistor connected between the output terminal of the preceding voltage divider and the inverting human terminal of the differential amplifier. An AC signal is input to the inverting input terminal of the differential amplifier via the first resistor, and a connection between the capacitor and the resistor in the CR ln] path or the LR is input. 10. The FM modulator according to claim 9, wherein a connection between the inductor and the resistor in the circuit is connected to a non-inverting input terminal of the differential amplifier.

12. At least one of the first and second phase shift circuits has a first end connected to an inverting input terminal of the differential amplifier and a second end connected to the CR circuit or the LR circuit. A second resistor connected between the output terminal of the differential amplifier and the inverted human input terminal; and a third resistor having one end connected to the inverted input terminal of the differential amplifier and the other end grounded. AC signal is input to the inverting input terminal of the differential amplifier via the first resistor, and the connection between the capacitor and the resistor in the CR circuit or 10. The FM modulator according to claim 9, wherein a connection between the inductor and the resistor in the LR circuit is connected to a non-inverting input terminal of the differential amplifier.

1 3. At least one of the first and second phase shift circuits is connected to a voltage divider composed of first and second resistors having substantially equal resistance values, and an output terminal of the voltage divider is provided. Or the potential difference between the potential of the capacitor and the connection point of the resistor in the CR circuit, or the potential of the output terminal of the voltage divider circuit and the ¾t of the connection point of the inductor and the resistance in the LR circuit. Potential difference

10. The FM modulator according to claim 9, wherein the output is amplified by a dynamic amplifier at a predetermined amplification factor.

14. A non-inverting circuit that outputs a signal without changing the phase of a signal is connected to a part of a feedback loop formed by cascading the first and second phase shift circuits. The connection order of the capacitance element or the reactance element consisting of the inductance element of the LR circuit and the resistance in the CR circuit or the resistance in the LR circuit is defined by 10. The FM modulator according to claim 9, wherein each of the two phase shift circuits is the same.

1 5. A phase inverting circuit for changing the phase of a signal and outputting the signal is connected to the-part of a feedback loop formed by cascading the first and second phase shift circuits, and the CR circuit is provided. The connection order of the capacitor in the LR circuit or the reactance element consisting of the inductor in the LR circuit and the resistance in the CR circuit or the resistance in the LR circuit is reversed for each of the two phase shift circuits. 10. The FM modulator according to claim 9, wherein:

16. At least one of the CR circuit and the dil L R circuit includes a variable resistor or a variable capacitance element,

The FM modulator according to claim 9, wherein the carrier frequency of the FM-modulated signal is varied by changing a resistance value of the variable resistor or a capacitance of the variable capacitance element. .

17. Conversion means for converting a human-powered AC signal into in-phase and out-of-phase AC signals and outputting the same, and converting one AC signal converted by the conversion means to the other AC through one end of a CR circuit. Two all-pass type phase shift circuits including synthesis means for synthesizing a signal through the other end of the CR circuit;

A non-inverting circuit that outputs the input AC signal without changing the phase,

The two phase-shift circuits and the non-inverting circuit are cascaded in a predetermined order, and the output of the last-stage circuit is fed back to the human-powered side of the first-stage [E] path. By using a condenser microphone as a capacitor in the CR circuit included in either of the two circuits, an FM-modulated signal is output from one of the two phase shift circuits, and the capacitor and the resistor in the CR circuit are output. Characterized in that the order of connection with the two phase shift circuits is reversed.

18. The pre-d conversion means in the two phase shift circuits includes a transistor, and a source and a drain of the transistor, or a resistor having substantially the same resistance value connected to an emitter and a collector, respectively, are connected to the transistor. An AC signal is inputted to a gate or a base in the evening, and the CR path constituting the synthesizing means is connected between a source and a drain of the transistor or between an emitter and a collector. 17. The FM modulator according to claim 17, wherein

1 9. At least one of the CR circuits includes a variable resistor or a variable capacitance element,

18. The FM modulator according to claim 17, wherein a carrier frequency of the FM-modulated signal is varied by changing a resistance value of the variable resistor or a capacitance of the variable capacitance element. .

20. A conversion means for converting the input AC signal into an in-phase and an in-phase AC signal and outputting the converted signal, and the negative AC signal converted by the conversion means via one end of the CR circuit to the other side. Two all-pass type phase shift circuits including synthesis means for synthesizing the AC signal through the other end of the CR circuit;

A phase inverting circuit for inverting the phase of the input AC ίΓί ^ and outputting the inverted AC, and vertically connecting the two phase shifting circuits and the phase inverting circuit in a predetermined order; To the input side of the first-stage circuit, and by using a condenser microphone as a capacitor in the CR circuit included in one of the two phase-shift circuits, a signal from one of the two phase-shift circuits is obtained. F. An FM modulator, which outputs a modulated signal, and wherein the connection order of the front capacitor and the resistor in the CR circuit is the same in the two phase shift circuits.

2 1. The conversion means in the two phase shift circuits include a transistor, and a source and a drain or an emitter and a collector of the transistor are connected to resistors having substantially equal resistance values, and the transistor is connected to the transistor. An AC signal is input to a gate or a base in the evening, and the CR circuit constituting the synthesizing means is connected between a source and a drain of the transistor or between an emitter and a collector of the transistor. FM modulator according to claim 20.

22. At least one of the CR circuits includes a variable resistor or a variable capacitance element,

The FM carrier according to claim 20, wherein a carrier frequency of said FM-modulated signal is varied by changing a resistance value of said variable resistor or a capacitance of said variable capacitor f. Modulation device.

2 3. The first to convert the input AC signal into an in-phase and anti-phase AC signal and output it. And one AC signal converted by the first conversion means is synthesized via the-end of the CR circuit, and the other AC signal is synthesized via the other end of the CR circuit. An all-pass type first phase shift circuit including a synthesis stage of

A second converting means for converting the input AC signal into an in-phase and an opposite-phase AC signal and outputting the AC signal; and converting one of the AC signals converted by the second converting means via one end of the LR circuit An all-pass second phase-shift circuit including second synthesizing means for synthesizing the other AC signal via the other end of the LR circuit;

The first and second phase shift circuits and the non-inverting circuit are cascaded in a predetermined order, and the output of the last-stage circuit is fed back to the input side of the first-stage circuit. By using a condenser microphone as a capacitor in the previous d CR circuit included in one of the two phase shift circuits, the FM-modulated signal is output from one of the two phase shift circuits, and The order of connection between the capacity element in the CR circuit or the reactance element consisting of the inductance element in the LR circuit and the resistance in the CR circuit or the resistance in the LR circuit is the same for each of the two phase shift circuits. FM modulation device characterized by the following.

24. The conversion means in the first and second phase shift circuits includes a transistor, and a source and a drain of the transistor, or an emitter and a collector, which are connected with resistors having substantially equal resistances, respectively. An AC signal is input to the gate or base of the transistor, and the CR circuit or the LR circuit constituting the synthesizing means is connected between the source and drain of the transistor or between the emitter and the collector. The FM modulator according to claim 23, wherein the frequency modulation is performed.

25. At least one of the front CR circuits includes a variable resistor or a variable capacitance element.

The FM carrier according to claim 23, wherein a carrier frequency of the FM-modulated signal is varied by changing a resistance value of the variable resistor or a capacitance _¾ of the variable capacitor element. Modulation device.

26. First conversion means for converting the input AC signal ¹ into in-phase and opposite-phase AC signals and outputting the same, and converting one of the AC signals converted by the first conversion means into a CR "port I A first phase shift circuit of an all-pass type including, via one end of the path, first synthesizing means for synthesizing the other AC signal through the other end of the CR path;

A second converter for converting the input AC signal into an in-phase and an opposite-phase AC signal and outputting the AC signal; and converting one of the AC signals converted by the second converter into one end of an LR circuit. An all-pass second phase-shift circuit including second synthesizing means for synthesizing the other AC signal via the other end of the LR circuit;

A phase inverting circuit for inverting the phase of the input AC signal and outputting the inverted signal, cascade-connecting the first and second phase shifting circuits and the phase inverting circuit in a predetermined order, The output of the circuit is fed back to the input side of the first stage circuit, and a condenser microphone is used as a capacity in the CR circuit included in one of the first and second phase shift circuits. An FM-modulated signal is output from one of the two phase shift circuits, and a capacitor in the CR circuit or a reactance element including an inductor in the LR circuit and a resistor in the CR circuit or the LR circuit described above. Characterized in that the order of connection with the internal resistors is reversed for each of the two phase shift circuits.

27. The conversion means in the first and second phase shift circuits includes a transistor, and the source and the drain of the transistor or the emitter and the collector have resistances substantially equal to each other. An AC signal is input to the gate or base of the transistor, and the CR circuit or the LR circuit constituting the gd synthesizing means is connected between the source and the drain of the transistor or between the emitter and the collector. 27. The FM modulator according to claim 26, wherein the frequency modulation is performed.

28. At least one of the CR circuit and the LR circuit includes a variable resistor or a variable capacitance element,

27. The carrier of the FM-modulated signal is varied by changing the resistance value of the variable resistor or the capacitance of the variable capacitance element, and the wave number is varied. FM modulator.