Electronic signal orthogonal homodyne phase measurement circuit

Abstract

An electronic signal orthogonal homodyne phase measurement circuit relates to the field of electronic technology and radio and television, solves the problems that the amplitude heights of two input signals are required to be equal, the measurement precision is not high and the structure of a measurement circuit is complex in the prior art, and comprises two signal input ends, resistors R1-R11, capacitors C1-C4 and diodes D1-D4, operational amplifiers U1 to U3 and an output end; the device adopts an operational amplifier to measure two input signals in a superposition manner; when the device is used for measuring the phase difference of the two signals, the output voltage of the device is in direct proportion to the amplitude of the smaller signal in the two input signals multiplied by the cosine value corresponding to the phase difference of the two signals; when the phase difference of the two cosine input signals is 90 degrees and the two cosine input signals are orthogonal, the output voltage of the device is always zero no matter what the amplitudes of the two input signals change, so that the amplitudes of the two input signals are not required to be equal when the device is used in an orthogonal phase discrimination occasion.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic technology and broadcast television field, concretely relates to a kind of electronic signal quadrature homodyne phase measuring circuit, the device is applied in frequency synthesizer as phase detector, can generate two mutually orthogonal signals, for the design of quadrature mixing device, in digital television and broadcast system, quadrature modulation can ensure the quality of signal stable transmission, quadrature demodulation can extract and restore video and audio signal. BACKGROUND

[0002] The measurement of electronic signal phase difference is essential in many scientific and technological fields and applications. In communication systems, accurate measurement of phase difference is crucial for signal synchronization demodulation, which ensures the accuracy and stability of data transmission. In the field of electronic engineering, phase difference measurement technology is widely used in the testing of frequency synthesizers, signal reconstruction processing, and the optimization design of filters, providing strong support for the performance improvement of electronic devices. In addition, radio signal interferometer can accurately determine the direction of the signal source by precisely measuring the phase difference of electronic signals. In the field of broadcasting and television, the widespread application of quadrature modulation and demodulation technology is due to the accurate measurement and control of phase difference, which ensures the transmission quality of program sound and image, providing clear and stable audio-visual experience for the audience. In the measurement of analog signal phase difference, existing phase detectors mostly use zero-crossing comparators to convert analog cosine signals into square waves, and then use related patents ZL201610342982.1 "Automatic digital phase detection circuit and system for signal phase difference of 0 to 2π", ZL201810401226.0 "Device and method for measuring electronic signal phase difference by random frequency sampling probability", and ZL201810399631.3 "Device and method for measuring electronic signal phase difference by coprime frequency sampling probability" to phase the square wave; because the zero-crossing comparator only uses the information at the zero-crossing point of the cosine signal, the error is large when there is an interference signal; patent 201810090361.8 "Electronic signal phase difference measurement device and method" provides a circuit device that can fully utilize the entire cosine signal information, which uses an automatic gain controller to make the amplitudes of two input signals the same, and then measures the phase difference by superimposing the signals. Because there are two automatic gain controllers, the circuit complexity is increased, and the automatic gain controller itself has an error; the utility model is improved on this basis, using an operational amplifier to directly process two input signals, which does not require the amplitudes of two input signals to be equal in quadrature phase detection applications. UTILITY MODEL CONTENT

[0003] The utility model discloses a kind of electronic signal quadrature homodyne phase measurement circuits, which is used to solve the problem of the requirement of the amplitude of two input signals being equal in the measurement of the phase difference of the existing electronic signal, and the problem of low measurement accuracy and complex measurement circuit structure.

[0004] The electronic signal quadrature homodyne phase measurement circuit comprises a signal input terminal INA, a signal input terminal INB, resistors R1-R11, capacitors C1-C4, diodes D1-D4, operational amplifiers U1-U3, and an output terminal OUTP.

[0005] The signal input terminal INA is connected to one end of the resistor R1 and one end of the resistor R4.

[0006] The signal input terminal INB is connected to one end of the resistor R2 and one end of the resistor R3.

[0007] The other end of the resistor R1 is connected to one end of the resistor R6, the negative input terminal of the operational amplifier U1, the positive terminal of the diode D1, and the other end of the resistor R2.

[0008] The other end of the resistor R3 is connected to one end of the resistor R9, the positive terminal of the diode D2, and the negative input terminal of the operational amplifier U2.

[0009] The other end of the resistor R4 is connected to the positive input terminal of the operational amplifier U2 and one end of the resistor R5.

[0010] The output terminal of the operational amplifier U1 is connected to the negative terminal of the diode D1 and the positive terminal of the diode D3.

[0011] The other end of the resistor R6 is connected to the negative terminal of the diode D3, one end of the resistor R7, and one end of the capacitor C2.

[0012] The other end of the resistor R7 is connected to one end of the capacitor C1, one end of the resistor R8, and the negative input terminal of the operational amplifier U3.

[0013] The positive input terminal of the operational amplifier U2 is connected to one end of the resistor R4 and one end of the resistor R5.

[0014] The output terminal of the operational amplifier U2 is connected to the negative terminal of the diode D2 and the positive terminal of the diode D4.

[0015] The negative terminal of the diode D4 is connected to the other end of the resistor R9, one end of the resistor R10, and one end of the capacitor C3.

[0016] The other end of the resistor R10 is connected to the positive input terminal of the operational amplifier U3, one end of the capacitor C4, and one end of the resistor R11.

[0017] The output end of the operational amplifier U3 is connected with the other end of the resistance R8, the other end of the capacitor C1 and the output end OUTP respectively;

[0018] The positive input end of the operational amplifier U1 is connected with the other end of the capacitor C2, the other end of the resistance R5, the other end of the capacitor C3, the other end of the capacitor C4 and the other end of the resistance R11, all of which are grounded;

[0019] The positive power supply end of the operational amplifier U1 is connected with the positive power supply end of the operational amplifier U2, and the positive power supply end of the operational amplifier U3 is connected with the positive power supply VCC;

[0020] The negative power supply end of the operational amplifier U1 is connected with the negative power supply end of the operational amplifier U2, and the negative power supply end of the operational amplifier U3 is connected with the negative power supply VEE.

[0021] The utility model discloses the beneficial effect:

[0022] The circuit design of the utility model makes full use of the comprehensive information of cosine signal in the whole period, so that random noise interference can be significantly suppressed, when the phase difference of two input signals is measured, the unique advantage of the circuit lies in that the measurement result of output voltage only depends on the amplitude of the smaller one of two input voltage signals, and is irrelevant to the signal with larger amplitude, and this characteristic makes the phase detection accuracy of the utility model be significantly improved compared with the existing traditional phase measurement circuit, further, in the application scene of quadrature phase detection, the utility model does not have strict restriction to the amplitude of two input signals, compared with the traditional analog phase detection which usually needs two signal channels to keep high balance, the circuit of the utility model greatly relaxes the use condition and can be more flexible and convenient in practical application.

[0023] The utility model discloses the phase measurement circuit does not use multiplier, and adopts operational amplifier superposition measurement two input signals, when being used for measuring the phase difference of two signals, the output voltage of device is proportional to the amplitude of the smaller one of two input signals and the cosine value corresponding to the phase difference of two signals, especially when two cosine input signals are orthogonal to each other and the phase difference is 90 degrees, no matter the amplitude of two input signals changes, the output voltage of the device is always zero, so when being used in quadrature phase detection, the amplitude of two input signals does not need to be equal.

[0024] The phase measurement circuit, when the voltage value of the output end OUTP is zero, indicates that the two input signals present a kind of orthogonal relationship; especially when the device is applied to the orthogonal phase discrimination scene, the output of zero indicates that the signal orthogonal characteristic is irrelevant to the amplitude of the two signals, and a signal orthogonal judgment mechanism independent of the amplitude is exhibited; therefore, this property makes the phase measurement circuit of the embodiment have great convenience when designing the frequency synthesizer in the quadrature mixer.

[0025] The phase measurement circuit can be used in the frequency synthesizer and used as a phase discriminator, and the error voltage obtained after phase discrimination is used to control the voltage-controlled oscillator, so as to accurately generate a second local oscillation signal orthogonal to the local oscillation reference signal. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The utility model discloses an electronic signal quadrature homodyne phase measurement circuit structure diagram. DETAILED DESCRIPTION

[0027] In combination Figure 1 The electronic signal quadrature homodyne phase measurement circuit includes a signal input end INA, a signal input end INB, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, capacitors C1, C2, C3, C4, diodes D1, D2, D3, D4, operational amplifiers U1, U2 and U3, an output end OUTP, a positive power supply VCC and a negative power supply VEE.

[0028] The signal input end INA is connected with the resistor R1 and the resistor R4, and the signal input end INB is connected with the resistor R2 and the resistor R3.

[0029] The negative input end of the operational amplifier U1 is electrically connected with the resistor R1, the resistor R2, the resistor R6 and the positive end of the diode D1, and the output end of the operational amplifier U1 is connected with the negative end of the diode D1 and the positive end of the diode D3.

[0030] The negative input end of the operational amplifier U2 is connected with the resistor R3, the resistor R9 and the positive end of the diode D2, and the positive input end of the operational amplifier U2 is connected with the resistor R4 and the resistor R5.

[0031] The output end of the operational amplifier U2 is connected with the negative end of the diode D2 and the positive end of the diode D4, and the negative end of the diode D3 is connected with the resistor R6, the resistor R7 and the capacitor C2.

[0032] The negative terminal of diode D4 is connected with resistor R9, resistor R10 and capacitor C3;

[0033] The negative terminal of operational amplifier U3 is connected with resistor R7, resistor R8 and capacitor C1;

[0034] The positive terminal of operational amplifier U3 is connected with resistor R10, resistor R11 and capacitor C4;

[0035] The output terminal of operational amplifier U3 is connected with resistor R8, capacitor C1 and output terminal OUTP;

[0036] The positive power supply terminal of operational amplifier U1 is connected with the positive power supply terminal of operational amplifier U2 and the positive power supply terminal of operational amplifier U3 and the positive power supply VCC;

[0037] The negative power supply terminal of operational amplifier U1 is connected with the negative power supply terminal of operational amplifier U2 and the negative power supply terminal of operational amplifier U3 and the positive power supply VCC;

[0038] The positive input terminal of operational amplifier U1 is connected with capacitor C2, resistor R5, capacitor C3, capacitor C4 and resistor R11.

[0039] In the embodiment, two input signals are introduced into the phase measurement circuit via signal input terminal INA and signal input terminal INB respectively for phase measurement;

[0040] The first signal with amplitude A1 is input from signal input terminal INA and passes through resistor R1; the second signal with amplitude A2 is input from signal input terminal INB and passes through resistor R2; the two signals are converged at the negative input terminal of operational amplifier U1, realizing the addition of the two input signals and obtaining the resultant signal after addition. Meanwhile, the first signal is subjected to voltage division by resistors R4 and R5 and is guided to the positive input terminal of operational amplifier U2; the second signal passes through resistor R3 and reaches the negative input terminal of operational amplifier U2, thus completing the subtraction of the two input signals and obtaining the resultant signal after subtraction.

[0041] In the circuit design of the phase measurement circuit in the embodiment, the resistance value of resistor R1 is required to be equal to that of resistor R2, the resistance value of resistor R3 is required to be equal to that of resistor R5, and the resistance value of resistor R4 is required to be equal to that of resistor R9. In addition, the ratio of resistor R6 to resistor R1 is required to be equal to the ratio of resistor R9 to resistor R3. In order to simplify the circuit design and reduce the types of components, the preferred design scheme is to make resistors R1, R2, R3 and R4 have the same resistance value, and make resistors R5 and R6 and resistor R7 have the same resistance value.

[0042] The sum signal after the operation amplifier U1 is rectified by diode D3 and filtered by capacitor C2, and the amplitude X of the sum signal is obtained on capacitor C2. The difference signal is rectified by diode D4 and filtered by capacitor C3, and the amplitude Y of the difference signal is obtained on capacitor C3. Then, the amplitude X of the sum signal is sent to the negative input terminal of the operation amplifier U3 through resistor R7, and the amplitude Y of the difference signal is sent to the positive input terminal of the operation amplifier U3 through resistor R10.

[0043] The operation amplifier U3 and resistors R7, R8, R10 and R11 form a subtraction circuit, which subtracts the amplitude Y of the difference signal from the amplitude X of the sum signal and sends the result to the output terminal OUTP. The voltage of the output terminal OUTP is measured by an external circuit, and then the phase difference Φ of the first signal and the second signal is calculated by the following formula:

[0044] If A1 is less than or equal to A2, the phase difference of the two signals is obtained by formula (1);

[0045]

[0046] Otherwise, the phase difference of the two signals is obtained by formula (2);

[0047]

[0048] In this embodiment, capacitor C1 is connected between the negative input terminal and the output terminal of operation amplifier U3, and capacitor C4 is connected between the positive input terminal of operation amplifier U3 and ground. This circuit design not only makes operation amplifier U3 serve as the core component of a subtractor, but also realizes the function of an integrator through the cooperation of the connected resistors and capacitors. Thanks to this structure, the entire circuit system exhibits significant suppression effect on random noise and accidental interference signals.

[0049] For the resistors connected to operation amplifier U3, the resistance value of resistor R7 is equal to that of resistor R10, and the resistance value of resistor R8 is equal to that of resistor R11.

[0050] In the design process of the phase measurement circuit described in this embodiment, the sensitivity of the phase measurement circuit for measuring weak input signals can be finely set by adjusting the resistance values of resistors R1, R6, R7 and R8. The core of this design is reflected in the voltage value of the output terminal OUTP, which is accurately expressed as a function of the two input signals, as shown in formula (3);

[0051]

[0052] In formula (3), MIN(A1, A2) represents the smaller value between the first signal amplitude A1 and the second signal amplitude A2, and represents the phase difference between the first signal and the second signal.

[0053] As can be seen from formula (3), when the voltage value of the output end OUTP of the circuit is zero, it indicates that the two input signals are in a quadrature relationship; in particular, when the device is applied to a quadrature phase detection scenario, the output of zero indicates that the signal quadrature characteristic is independent of the amplitudes of the two signals, and a signal quadrature judgment mechanism independent of the amplitude is exhibited; therefore, this property makes the phase detection circuit of the embodiment have great convenience in designing a frequency synthesizer in a quadrature mixer; specifically, the phase detection circuit can be used as a phase detector in the frequency synthesizer, and the error voltage obtained after phase detection is used to control a voltage-controlled oscillator, so as to accurately generate a second local oscillation signal orthogonal to a local oscillation reference signal.

[0054] The technical features of the above-described embodiments can be combined in any manner, and to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the description.

[0055] The above-described embodiments only express several implementation manners of the utility model, the description is more specific and detailed, but it should not be understood as a limitation on the scope of the utility model patent. It should be pointed out that for ordinary skilled persons in the art, on the premise of not departing from the concept of the utility model, a number of modifications and improvements can be made, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. An electronic signal quadrature phase detection circuit, characterised in that: The circuit comprises signal input terminal INA, signal input terminal INB, resistors R1-R11, capacitors C1-C4, diodes D1-D4, operational amplifiers U1-U3 and output terminal OUTP; The signal input terminal INA is connected with one end of resistor R1 and one end of resistor R4; The signal input terminal INB is connected with one end of resistor R2 and one end of resistor R3; The other end of resistor R1 is connected with one end of resistor R6, negative input terminal of operational amplifier U1, positive terminal of diode D1 and the other end of resistor R2 respectively; The other end of resistor R3 is connected with one end of resistor R9, positive terminal of diode D2 and negative input terminal of operational amplifier U2 respectively; The other end of resistor R4 is connected with positive input terminal of operational amplifier U2 and one end of resistor R5 respectively; The output terminal of operational amplifier U1 is connected with negative terminal of diode D1 and positive terminal of diode D3; The other end of resistor R6 is connected with negative terminal of diode D3, one end of resistor R7 and one end of capacitor C2 respectively; The other end of resistor R7 is connected with one end of capacitor C1, one end of resistor R8 and negative input terminal of operational amplifier U3 respectively; The positive input terminal of operational amplifier U2 is connected with one end of resistor R4 and one end of resistor R5; The output terminal of operational amplifier U2 is connected with negative terminal of diode D2 and positive terminal of diode D4 respectively; The negative terminal of diode D4 is connected with the other end of resistor R9, one end of resistor R10 and one end of capacitor C3 respectively; The other end of resistor R10 is connected with positive input terminal of operational amplifier U3, one end of capacitor C4 and one end of resistor R11 respectively; The output terminal of operational amplifier U3 is connected with the other end of resistor R8, the other end of capacitor C1 and output terminal OUTP respectively; The positive input terminal of operational amplifier U1 is grounded, and the other end of capacitor C2, the other end of resistor R5, the other end of capacitor C3, the other end of capacitor C4 and the other end of resistor R11 are also grounded; The positive power supply terminal of operational amplifier U1 is connected with the positive power supply terminal of operational amplifier U2, and the positive power supply terminal of operational amplifier U3 is connected with positive power supply VCC; The negative power supply terminal of operational amplifier U1 is connected with the negative power supply terminal of operational amplifier U2, and the negative power supply terminal of operational amplifier U3 is connected with negative power supply VEE.

2. The electronic signal quadrature homodyne phase detection circuit of claim 1, wherein: The resistance values of resistor R1 and resistor R2 are equal, the resistance value of resistor R3 is equal to that of resistor R5, and the resistance value of resistor R4 is equal to that of resistor R9.

3. The electronic signal quadrature homodyne phase detection circuit of claim 1, wherein: The ratio of resistor R6 to resistor R1 is equal to the ratio of resistor R9 to resistor R3.

4. The electronic signal quadrature homodyne phase detection circuit of claim 1, wherein: The resistance values of resistor R5, resistor R6 and resistor R7 are equal.

5. The electronic signal quadrature homodyne phase detection circuit of claim 1, wherein: The resistance value of resistor R7 is equal to that of resistor R10, and the resistance value of resistor R8 is equal to that of resistor R11.

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