Differential modulation circuit

Abstract

The utility model provides a differential modulation circuit. The differential modulation circuit comprises a three-end-to-single-end modulation circuit and a single-end-to-differential conversion circuit. Differential input signals are accessed to two input ends of the three-end to single-end modulation circuit; the third input end of the three-end-to-single-end modulation circuit is connected with the output end of the local oscillator; the output end of the three-end-to-single-end modulation circuit is connected with the input end of the single-end-to-differential conversion circuit, and the two output ends of the single-end-to-differential conversion circuit are the two output ends of the modulation circuit. The circuit can suppress noise and improve the balance of differential signals.

Description

Technical Field

[0001] This utility model relates to the technical field of modulation circuits, and more specifically, to a differential modulation circuit. Background Technology

[0002] In differential circuits, ideally, the two differential signals should be perfectly complementary, meaning they have equal amplitudes and opposite phases. However, factors such as component parameter deviations, temperature variations, and power supply fluctuations can lead to imbalances in the differential signals, manifesting as inconsistent amplitudes or phase deviations. This imbalance causes signal distortion, increases harmonic distortion, reduces system linearity, and may even introduce additional noise. Utility Model Content

[0003] The purpose of this utility model embodiment is to provide a differential modulation circuit that solves the above-mentioned problems existing in the prior art, suppresses noise, and improves the balance of differential signals.

[0004] In a first aspect, a differential modulation circuit is provided, which may include: a three-terminal to single-terminal modulation circuit and a single-terminal to differential conversion circuit;

[0005] Two input terminals of the three-terminal to single-terminal modulation circuit are connected to differential input signals; the third input terminal of the three-terminal to single-terminal modulation circuit is connected to the output terminal of the local oscillator.

[0006] The output terminal of the three-terminal to single-terminal modulation circuit is connected to the input terminal of the single-terminal to differential conversion circuit, and the two output terminals of the single-terminal to differential conversion circuit are the two output terminals of the modulation circuit.

[0007] In one possible implementation, the three-terminal to single-terminal modulation circuit includes an operational amplifier and a signal mixing circuit;

[0008] The two input terminals of the operational amplifier are the two input terminals of the three-terminal to single-terminal modulation circuit;

[0009] The output terminal of the operational amplifier is connected to the first input terminal of the signal mixing circuit, and the second input terminal of the signal mixing circuit is the third input terminal of the three-terminal to single-terminal modulation circuit.

[0010] The output terminal of the signal mixing circuit is the output terminal of the three-terminal to single-terminal modulation circuit.

[0011] In one possible implementation, the signal mixing circuit is a signal summing circuit or a signal multiplication circuit.

[0012] In one possible implementation, the operational amplifier is an LM101A operational amplifier.

[0013] In one possible implementation, the single-ended to differential converter circuit includes one transformer, two capacitors, and three resistors;

[0014] One end of the transformer is connected to the output of a three-terminal to single-terminal modulation circuit via a resistor, and the other end of the transformer is grounded.

[0015] The first end of the other side of the transformer is grounded through a resistor and a capacitor connected in series, and the intersection of the resistor and the capacitor is an output terminal of the single-ended to differential conversion circuit.

[0016] The second end of the other side of the transformer is also grounded through a resistor and a capacitor connected in series, and the intersection of the resistor and the capacitor is the other output end of the single-ended to differential conversion circuit.

[0017] In one possible implementation, the two capacitors on the other side of the transformer have the same capacitance value, and the two resistors have the same resistance value.

[0018] In one possible implementation, the circuit further includes: a signal amplification circuit;

[0019] The two input terminals of the signal amplification circuit are respectively connected to the two output terminals of the single-ended to differential conversion circuit to amplify the signal output by the single-ended to differential conversion circuit.

[0020] The differential modulation circuit provided by this utility model includes a three-terminal to single-terminal modulation circuit and a single-terminal to differential conversion circuit. Two input terminals of the three-terminal to single-terminal modulation circuit are connected to differential input signals. The third input terminal of the three-terminal to single-terminal modulation circuit is connected to the output terminal of a local oscillator. The output terminal of the three-terminal to single-terminal modulation circuit is connected to the input terminal of the single-terminal to differential conversion circuit, and the two output terminals of the single-terminal to differential conversion circuit are the two output terminals of the modulation circuit. This circuit can suppress noise and improve the balance of the differential signal. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments of this utility model will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A schematic diagram of a differential modulation circuit provided in an embodiment of this utility model;

[0023] Figure 2A schematic diagram of a three-terminal to single-terminal modulation circuit provided for an embodiment of this utility model;

[0024] Figure 3 This is a schematic diagram of a single-ended to differential conversion circuit provided in an embodiment of the present invention. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model. Unless otherwise defined, the technical or scientific terms used in the present utility model should have the ordinary meaning understood by those skilled in the art to which the present utility model pertains. The words "first," "second," and similar terms used in the present utility model do not indicate any order, quantity, or importance, but are only used to distinguish different components. The words "comprising" or "including," etc., mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but does not exclude other elements or objects. The words "connection," "coupled," or "linked," etc., are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," and "right" are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0026] A transformer converts an input signal into an output signal through electromagnetic coupling. In differential signal applications, the primary side of the transformer is connected to a single-ended or differential signal, while the secondary side generates a pair of differential signals. Ideally, the transformer can ensure that the two differential output signals have the same amplitude and opposite phase, thus achieving good balance.

[0027] Figure 1 A differential modulation circuit provided for an embodiment of this utility model, such as Figure 1 As shown, the circuit may include:

[0028] Three-terminal to single-terminal modulation circuit 100 and single-terminal to differential conversion circuit 200;

[0029] Two input terminals of the three-terminal to single-terminal modulation circuit 100 are connected to differential input signals; the third input terminal of the three-terminal to single-terminal modulation circuit 100 is connected to the output terminal of the local oscillator.

[0030] The output of the three-terminal to single-terminal modulation circuit 100 is connected to the input of the single-terminal to differential conversion circuit 200. The two outputs of the single-terminal to differential conversion circuit 200 are the two outputs of the modulation circuit.

[0031] The three-terminal to single-terminal modulation circuit 100 is used to amplify the differential input signal, mix the amplified differential input signal with the oscillator signal generated by the local oscillator, and output the signal.

[0032] The single-ended to differential converter circuit 200 is used to convert a mixed single signal into a differential signal.

[0033] The signal mixing circuit is either a signal summing circuit or a signal multiplication circuit, and can be configured according to service requirements. This application does not impose any restrictions on it.

[0034] Combination Figure 2 As shown, the three-terminal to single-terminal modulation circuit 100 may include an operational amplifier 110 and a signal mixing circuit 120;

[0035] The two input terminals of the operational amplifier 110 are the two input terminals of the three-terminal to single-terminal modulation circuit 100;

[0036] The output terminal of the operational amplifier 110 is connected to the first input terminal of the signal mixing circuit 120, and the second input terminal of the signal mixing circuit 120 is the third input terminal of the three-terminal to single-terminal modulation circuit 100.

[0037] The output of the signal mixing circuit 120 is the output of the three-terminal to single-terminal modulation circuit 100.

[0038] In some embodiments, the operational amplifier is an LM101A operational amplifier.

[0039] like Figure 3 As shown, the single-ended to differential converter circuit 200 may include one transformer, two capacitors (such as C1 and C2) and three resistors (such as R1, R2 and R3); the two capacitors have the same capacitance value, and the resistors R2 and R3 have the same resistance value.

[0040] One end of the transformer is connected to the output of the three-terminal to single-terminal modulation circuit 100 through a resistor R1, and the other end of the transformer is grounded.

[0041] The first end of the other side of the transformer is grounded through a resistor R2 and a capacitor C1 connected in series, and the intersection of the resistor R2 and the capacitor C1 is an output terminal of the single-ended to differential conversion circuit 200.

[0042] The second end of the other side of the transformer is also grounded through a resistor R3 and a capacitor C2 connected in series, and the intersection of the resistor R3 and the capacitor C2 is another output end of the single-ended to differential converter circuit 200.

[0043] Furthermore, the circuit may also include a signal amplification circuit;

[0044] The two input terminals of the signal amplification circuit are connected to the two output terminals of the single-ended to differential conversion circuit, respectively, to amplify the signal output by the single-ended to differential conversion circuit.

[0045] The differential modulation circuit provided by this utility model includes a three-terminal to single-terminal modulation circuit and a single-terminal to differential conversion circuit. Two input terminals of the three-terminal to single-terminal modulation circuit are connected to differential input signals. The third input terminal of the three-terminal to single-terminal modulation circuit is connected to the output terminal of a local oscillator. The output terminal of the three-terminal to single-terminal modulation circuit is connected to the input terminal of the single-terminal to differential conversion circuit, and the two output terminals of the single-terminal to differential conversion circuit are the two output terminals of the modulation circuit. This circuit can suppress noise and improve the balance of the differential signal.

[0046] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0047] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this utility model without departing from the spirit and scope of the embodiments of this utility model. Therefore, if these modifications and variations to the embodiments of this utility model fall within the scope of the claims in this utility model and their equivalents, then this utility model also intends to include these modifications and variations.

Claims

1. A differential modulation circuit, characterized in that, The circuit includes: a three-terminal to single-terminal modulation circuit and a single-terminal to differential conversion circuit; Two input terminals of the three-terminal to single-terminal modulation circuit are connected to differential input signals; the third input terminal of the three-terminal to single-terminal modulation circuit is connected to the output terminal of the local oscillator. The output terminal of the three-terminal to single-terminal modulation circuit is connected to the input terminal of the single-terminal to differential conversion circuit, and the two output terminals of the single-terminal to differential conversion circuit are the two output terminals of the modulation circuit.

2. The circuit as described in claim 1, characterized in that, The three-terminal to single-terminal modulation circuit includes an operational amplifier and a signal mixing circuit; The two input terminals of the operational amplifier are the two input terminals of the three-terminal to single-terminal modulation circuit; The output terminal of the operational amplifier is connected to the first input terminal of the signal mixing circuit, and the second input terminal of the signal mixing circuit is the third input terminal of the three-terminal to single-terminal modulation circuit. The output terminal of the signal mixing circuit is the output terminal of the three-terminal to single-terminal modulation circuit.

3. The circuit as described in claim 2, characterized in that, The signal mixing circuit is a signal summing circuit or a signal multiplication circuit.

4. The circuit as described in claim 2, characterized in that, The operational amplifier is an LM101A operational amplifier.

5. The circuit as described in claim 1, characterized in that, The single-ended to differential converter circuit includes one transformer, two capacitors, and three resistors; One end of the transformer is connected to the output of a three-terminal to single-terminal modulation circuit via a resistor, and the other end of the transformer is grounded. The first end of the other side of the transformer is grounded through a resistor and a capacitor connected in series, and the intersection of the resistor and the capacitor is an output terminal of the single-ended to differential conversion circuit. The second end of the other side of the transformer is also grounded through a resistor and a capacitor connected in series, and the intersection of the resistor and the capacitor is the other output end of the single-ended to differential conversion circuit.

6. The circuit as described in claim 5, characterized in that, The two capacitors on the other side of the transformer have the same capacitance value, and the two resistors have the same resistance value.

7. The circuit as described in claim 1, characterized in that, The circuit also includes: a signal amplification circuit; The two input terminals of the signal amplification circuit are respectively connected to the two output terminals of the single-ended to differential conversion circuit to amplify the signal output by the single-ended to differential conversion circuit.

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