Device for measuring amplitude and effective value of alternating current signal

Abstract

The utility model aims to provide the device for measuring the amplitude and the effective value of the alternating current signal, which is simple in structure and low in cost, can obtain the amplitude and the effective value of the original signal only by testing the output voltage, and is convenient to operate. The device comprises a partial pressure processing module, a buffer module and a signal processing module, an input signal is accessed to the partial pressure processing module, the partial pressure processing module is accessed to the signal processing module through the buffer module, and the signal processing module is connected with an external testing machine. The signal processing module comprises a radio frequency transceiver and a first operational amplifier, the radio frequency transceiver is connected with the buffer module, and both the radio frequency transceiver and the first operational amplifier are connected with an external testing machine. The utility model is applied to the technical field of AC signal measurement.

Description

Technical Field

[0001] The utility model is applied to the technical field of measuring alternating current signals, and particularly relates to a device for measuring the amplitude and effective value of an alternating current signal. Background Art

[0002] At present, most of the existing technologies use analog-to-digital converter chips to sample the original signal, and then sort and calculate the maximum value, minimum value, and root mean square of the collected signal to obtain the amplitude and effective value of the original signal. Or use a circuit built with an operational amplifier to process the signal and output the amplitude and effective value of the original signal. However, the scheme of using an analog-to-digital converter to collect the original signal is easily restricted by the sampling rate of the analog-to-digital converter itself and the cumbersome programming of the driver of the analog-to-digital converter; at the same time, the oscilloscope has the disadvantages of large size and high cost. Therefore, it is necessary to provide a device for measuring the amplitude and effective value of AC signals, which has a simple structure, low cost, only needs to test the output voltage to obtain the amplitude and effective value of the original signal, and is easy to operate. Utility Model Content

[0003] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a device for measuring the amplitude and effective value of an AC signal which has a simple structure, low cost, can obtain the amplitude and effective value of the original signal by only testing the output voltage, and is easy to operate.

[0004] The technical solution adopted by the utility model is: the utility model includes a voltage division processing module, a buffer module, and a signal processing module, the input signal is connected to the voltage division processing module, the voltage division processing module is connected to the signal processing module via the buffer module, the signal processing module is connected to an external tester, the signal processing module includes a radio frequency transceiver and a first operational amplifier, the radio frequency transceiver is connected to the buffer module, and the radio frequency transceiver and the first operational amplifier are both connected to the external tester.

[0005] It can be seen from the above scheme that compared with the traditional ADC scheme, the present application has the advantages of simple operation, no need to write programs, and no need to perform complex calculations on data; low cost, only a multimeter is needed to measure the output result, and there is no need to adjust too many devices according to the frequency and amplitude of the input signal; for the measurement scheme of the amplitude and effective value of the DC-6G highest signal, it is only necessary to test the output voltage to obtain the amplitude and effective value of the original signal.

[0006] A preferred solution is that the voltage division processing module includes a relay, the AC_INPUT pin of the relay is connected to the input signal, and the input signal is divided into two paths. The first path is divided by the first resistor and the second resistor, and 1 / 20 of the input signal can be obtained according to the ratio, and the parallel configuration of the first capacitor, the second capacitor, and the third capacitor is 1 / 19 of the parallel configuration of the fourth capacitor, the fifth capacitor, and the sixth capacitor according to the ratio; the second path is divided by the third resistor and the fourth resistor, and 1 / 5 of the input signal can be obtained according to the ratio, and the parallel configuration of the seventh capacitor, the eighth capacitor, and the ninth capacitor is 1 / 4 of the parallel configuration of the tenth capacitor, the eleventh capacitor, and the twelfth capacitor according to the ratio.

[0007] A preferred solution is that the buffer module includes a second operational amplifier, the non-inverting input terminal of the second operational amplifier is connected to the AC_INPUT_R pin of the relay, and the inverting input terminal and output terminal of the second operational amplifier are both connected to the RF_INPUT pin of the radio frequency transceiver.

[0008] A preferred solution is that the VENV pin of the radio frequency transceiver is connected to the non-inverting input terminal of the first operational amplifier, and the output terminal of the first operational amplifier and the VRMS pin of the radio frequency transceiver are connected to an external tester. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a structural block diagram of the utility model;

[0010] Figure 2 It is a system topology block diagram of the utility model;

[0011] Figure 3 is a circuit schematic diagram of the voltage division processing module and the buffer module;

[0012] Figure 4 is a circuit schematic diagram of the signal processing module;

[0013] Figure 5 is a system block diagram of the radio frequency transceiver;

[0014] Figure 6 The present invention is a circuit schematic diagram of measuring effective value by using an operational amplifier and a test chip in the prior art. DETAILED DESCRIPTION

[0015] like Figure 1 to Figure 2As shown, in this embodiment, the utility model includes a voltage division processing module 1, a buffer module 2, and a signal processing module 3. The input signal is connected to the voltage division processing module 1, and the voltage division processing module 1 is connected to the signal processing module 3 through the buffer module 2. The signal processing module 3 is connected to an external tester. The signal processing module 3 includes a radio frequency transceiver U800 and a first operational amplifier U801. The radio frequency transceiver U800 is connected to the buffer module 2, and the radio frequency transceiver U800 and the first operational amplifier U801 are both connected to an external tester. The model of the radio frequency transceiver U800 is ADL5511ACPZ-R7, and the model of the first operational amplifier U801 is INA826AIDGKR.

[0016] The absolute value of the power of the input signal is mostly limited to the range of -27dBm to 17dBm. If a signal exceeding the input range needs to be measured, the voltage division processing module 1 needs to reduce the input signal in proportion. Figure 2 For the voltage division type shown, the buffer module 2 is required to drive the subsequent measurement circuit, and the signal processing module 3 outputs the amplitude and effective value of the test signal.

[0017] like Figure 5 As shown,

[0018] The radio frequency transceiver U800 processes the measurement results of the amplitude and the effective value. The radio frequency transceiver U800 processes the input signal of the buffer module 2 and outputs three DC components, namely Vrms, Venv, and Vref. Vrms is the output after multiplying the real Vrms of the input signal by Gain = 1.7. Venv is the envelope of the input signal multiplied by the gain Gain = 1.5 and then outputted with the internal Vref as a reference. Vref is a fixed 1.1V reference voltage. Only Vpeak is needed here, so the first operational amplifier U801 is added at the back end, and Venv - Vref is Vpeak. The above processing obtains the Vpeak and Vrms of the output signal of the buffer module 2, and then multiplies it by the gain of the voltage divider circuit 5 or 20 according to the voltage divider ratio. The Vpeak and Vrms of the real signal are obtained. Among them, Vpeak refers to the amplitude of the AC signal (Vpeak) refers to the maximum or minimum voltage value reached by the AC signal. In one cycle. The AC signal will start from zero, pass through the maximum or minimum value, return to zero, and then pass through the opposite peak value. The amplitude is the distance from zero to the maximum or minimum value; Vrms refers to the effective value / root mean square value Vrms of the AC signal. It means squaring the signal in one cycle, integrating it, and then taking the square root and averaging it.

[0019] like Figure 3 As shown, in this embodiment, the voltage division processing module 1 includes a relay K700, and the AC_INPUT pin of the relay K700 is connected to the input signal. The input signal is divided into two routes for voltage transmission. The first route is a voltage division by the first resistor R700 and the second resistor R701. According to the ratio, 1 / 20 of the input signal can be obtained. According to the ratio, the parallel configuration of the first capacitor C702, the second capacitor C704, and the third capacitor C706 is 1 / 19 of the parallel configuration of the fourth capacitor C703, the fifth capacitor C705, and the sixth capacitor C707; the second route is a voltage division by the third resistor R702 and the fourth resistor R705. According to the ratio, 1 / 5 of the input signal can be obtained. According to the ratio, the parallel configuration of the seventh capacitor C708, the eighth capacitor C710, and the ninth capacitor C712 is 1 / 4 of the parallel configuration of the tenth capacitor C709, the eleventh capacitor C711, and the twelfth capacitor C713.

[0020] The voltage division processing module 1 realizes two forms of 5 times attenuation and 20 times attenuation through a voltage division network of resistors and capacitors. Different resistors and capacitors can be used to achieve different input impedance sizes, thereby testing and measuring the 13.56M OOK signal with an amplitude of ±5V. The user can arbitrarily configure the voltage division ratio and different resistance and capacitance sizes to design the input impedance.

[0021] like Figure 3 As shown, in this embodiment, the buffer module 2 includes a second operational amplifier U700, the same-direction input terminal of the second operational amplifier U700 is connected to the AC_INPUT_R pin of the relay K700, and the reverse input terminal and output terminal of the second operational amplifier U700 are connected to the RF_INPUT pin of the radio frequency transceiver U800. The model of the second operational amplifier U700 is AD8065ARTZ-REEL, and the buffer module 2 uses the second operational amplifier U700 to build a voltage follower to achieve the following purposes: the first function can be used as an operational amplifier with JFET level input to follow the original signal after voltage division with very small input bias current and input impedance; the second function can be applied to the use scenario of measuring the amplitude and effective value of the 13.56M signal, and the gain bandwidth product and slew rate of this operational amplifier also meet the design requirements; the third function can be used to check the output current capability of the operational amplifier to be 30mA for the back-end circuit input impedance must be 75Ω, which also meets the target requirements. Users need to select the target op amp based on their own usage environment and meet the above requirements in combination with the usage situation.

[0022] like Figure 4As shown, in this embodiment, the VENV pin of the radio frequency transceiver U800 is connected to the non-inverting input terminal of the first operational amplifier U801, and the output terminal of the first operational amplifier U801 and the VRMS pin of the radio frequency transceiver U800 are connected to an external tester.

[0023] like Figure 6 As shown, in this embodiment, the circuit of the prior art uses AD8361ARMZ-REEL7 to measure the effective value part, and uses two operational amplifiers and diodes to build an amplitude measurement circuit, which can also output the result correctly, but when used, it is necessary to constantly adjust the size of C609 according to the frequency of the input signal, and it is necessary to open Q600 to discharge C609 after the measurement. However, when the frequency changes, it is necessary to constantly adjust the value of the holding capacitor, and the operation is relatively cumbersome.

Claims

1. A device for measuring the amplitude and effective value of an AC signal, characterized in that: It comprises a voltage division processing module (1), a buffer module (2), and a signal processing module (3); an input signal is connected to the voltage division processing module (1); the voltage division processing module (1) is connected to the signal processing module (3) via the buffer module (2); the signal processing module (3) is connected to an external test machine; the signal processing module (3) comprises a radio frequency transceiver (U800) and a first operational amplifier (U801); the radio frequency transceiver (U800) is connected to the buffer module (2); and both the radio frequency transceiver (U800) and the first operational amplifier (U801) are connected to the external test machine.

2. The device for measuring the amplitude and effective value of an AC signal according to claim 1, characterized in that: The voltage division processing module (1) comprises a relay (K700), wherein an AC_INPUT pin of the relay (K700) is connected to an input signal, and the input signal is divided into two paths for voltage generation. The first path is divided by a first resistor (R700) and a second resistor (R701), and 1 / 20 of the input signal can be obtained according to a ratio. According to a ratio, the first capacitor (C702), the second capacitor (C704), and the third capacitor (C706) are configured in parallel to be 1 / 19 of the fourth capacitor (C703), the fifth capacitor (C705), and the sixth capacitor (C707) in parallel; the second path is divided by a third resistor (R702) and a fourth resistor (R705), and 1 / 5 of the input signal can be obtained according to a ratio. According to a ratio, the seventh capacitor (C708), the eighth capacitor (C710), and the ninth capacitor (C712) are configured in parallel to be 1 / 4 of the tenth capacitor (C709), the eleventh capacitor (C711), and the twelfth capacitor (C713) in parallel.

3. The device for measuring the amplitude and effective value of an AC signal according to claim 2, characterized in that: The buffer module (2) comprises a second operational amplifier (U700), the same-direction input terminal of the second operational amplifier (U700) is connected to the AC_INPUT_R pin of the relay (K700), and the reverse input terminal and output terminal of the second operational amplifier (U700) are both connected to the RF_INPUT pin of the radio frequency transceiver (U800).

4. The device for measuring the amplitude and effective value of an AC signal according to claim 1, characterized in that: The VENV pin of the radio frequency transceiver (U800) is connected to the non-inverting input terminal of the first operational amplifier (U801), and the output terminal of the first operational amplifier (U801) and the VRMS pin of the radio frequency transceiver (U800) are connected to an external tester.

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