Large dynamic local oscillator leakage suppression circuit system

Abstract

The invention relates to a large dynamic local oscillator leakage suppression circuit system, which comprises an RX receiving channel, the RX receiving channel comprises a first switch selection circuit, a 0 / 20dB attenuator and an amplifier, the first switch selection circuit, the 0 / 20dB attenuator and the amplifier are connected between a transmitter and a radio frequency transceiver chip, and the first switch selection circuit, the 0 / 20dB attenuator and the amplifier are connected in sequence. The 0 / 20dB attenuator comprises a first 0 / 20dB attenuator and a second 0 / 20dB attenuator, the amplifier comprises a first amplifier and a second amplifier, the input end of the first 0 / 20dB attenuator is connected with the negative electrode of the amplifier in the first switch selection circuit, the output end of the first 0 / 20dB attenuator is connected with the positive electrode of the first amplifier, and the negative electrode of the first amplifier is connected with the second 0 / 20dB attenuator. By adopting the large dynamic local oscillator leakage suppression circuit system, local oscillator leakage on an Rx path when a transmitter outputs low power is greatly suppressed, and the signal quality is improved. According to the invention, the influence on the power dynamic state of the RX is avoided, and meanwhile, the complexity of the circuit is reduced.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency microwaves, in particular to the field of multi-channel transceiver integrated chips, and specifically refers to a large dynamic local oscillator leakage suppression circuit system. Background Art

[0002] At present, conventional multi-channel transceiver integrated chips, transceivers, integrate the receiving and transmitting RF front-ends. The RF transceiver channel solutions are as follows: Figure 1 As shown. The TX transmission channel adjusts the power of the RF signal output by the RF transceiver chip to the target value through attenuators, switches, amplifiers and other devices, and then outputs it; the RX receiving channel adjusts the power of the received RF signal to the power supported by the RF transceiver chip through amplifiers, switches and other devices, and then inputs it. In this process, when the transmitter outputs a low-power signal, due to the general isolation between the transceiver channels of the RF transceiver chip, the local oscillator will leak into the Rx path, affecting the signal quality.

[0003] In the conventional transmit-receive channel solution, the switch on the Rx path is set to the straight path by default, which is equivalent to only the attenuation of the switch on the Rx path. The suppression of the local oscillator leakage is very small, and the leaked local oscillator signal will be directly output from the Rx port.

[0004] like Figure 1 As shown in the figure, it is a conventional RF transceiver channel solution. In this process, when the transmitter outputs a low-power signal, due to the general isolation between the transceiver channels of the RF transceiver chip, the local oscillator will leak into the Rx path, affecting the signal quality. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a large dynamic local oscillator leakage suppression circuit system which has simple structure, good signal quality and a wide range of applications.

[0006] In order to achieve the above object, the large dynamic local oscillator leakage suppression circuit system of the present invention is as follows:

[0007] The main feature of the large dynamic local oscillator leakage suppression circuit system is that the system includes an RX receiving channel, the RX receiving channel includes a first switch selection circuit, a 0 / 20dB attenuator and an amplifier, the first switch selection circuit, the 0 / 20dB attenuator and the amplifier are connected between the transmitter and the RF transceiver chip, and the first switch selection circuit, the 0 / 20dB attenuator and the amplifier are connected in sequence.

[0008] Preferably, the 0 / 20dB attenuator includes a first 0 / 20dB attenuator and a second 0 / 20dB attenuator, the amplifier includes a first amplifier and a second amplifier, the input end of the first 0 / 20dB attenuator is connected to the negative pole of the amplifier in the first switch selection circuit, the output end of the first 0 / 20dB attenuator is connected to the positive pole of the first amplifier, the negative pole of the first amplifier is connected to the second 0 / 20dB attenuator, and the positive pole of the second amplifier is connected to the second 0 / 20dB attenuator.

[0009] Preferably, the 0 / 20dB attenuator is used to select 20dB attenuation or no attenuation.

[0010] Preferably, the system further comprises a TX transmission channel, the TX transmission channel comprises three switch selection circuits and a 2×20 attenuator, the three switch selection circuits and the 2×20 attenuator are connected in sequence, the three switch selection circuits and the 2×20 attenuator are connected between the RF transceiver chip and the transmitter, and the three switch selection circuits and the 2×20 attenuator are connected in sequence.

[0011] The large dynamic local oscillator leakage suppression circuit system of the present invention greatly suppresses the local oscillator leakage on the Rx path when the transmitter outputs low power, thereby improving the signal quality. The present invention avoids affecting the power dynamics of the RX and reduces the complexity of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a conventional RF transceiver channel solution.

[0013] Figure 2 It is a circuit diagram of a large dynamic local oscillator leakage suppression circuit system of the present invention. DETAILED DESCRIPTION

[0014] In order to more clearly describe the technical content of the present invention, further description is given below in conjunction with specific embodiments.

[0015] The large dynamic local oscillator leakage suppression circuit system of the present invention includes an RX receiving channel, and the RX receiving channel includes a first switch selection circuit, a 0 / 20dB attenuator and an amplifier. The first switch selection circuit, the 0 / 20dB attenuator and the amplifier are connected between the transmitter and the RF transceiver chip, and the first switch selection circuit, the 0 / 20dB attenuator and the amplifier are connected in sequence.

[0016] As a preferred embodiment of the present invention, the 0 / 20dB attenuator includes a first 0 / 20dB attenuator and a second 0 / 20dB attenuator, the amplifier includes a first amplifier and a second amplifier, the input end of the first 0 / 20dB attenuator is connected to the negative pole of the amplifier in the first switch selection circuit, the output end of the first 0 / 20dB attenuator is connected to the positive pole of the first amplifier, the negative pole of the first amplifier is connected to the second 0 / 20dB attenuator, and the positive pole of the second amplifier is connected to the second 0 / 20dB attenuator.

[0017] As a preferred embodiment of the present invention, the 0 / 20dB attenuator is used to select attenuation of 20dB or no attenuation.

[0018] As a preferred embodiment of the present invention, the system also includes a TX transmission channel, which includes three switch selection circuits and a 2×20 attenuator, which are connected in sequence, and the three switch selection circuits and the 2×20 attenuator are connected between the RF transceiver chip and the transmitter, and the three switch selection circuits and the 2×20 attenuator are connected in sequence.

[0019] In a specific implementation of the present invention, the present invention needs to suppress the local oscillator leakage on the Rx path when the transmitter outputs low power to reduce the impact on signal quality. While suppressing the local oscillator leakage, it is necessary to avoid affecting the power dynamics of the RX.

[0020] The present invention provides a large dynamic local oscillator leakage suppression circuit, such as Figure 2 As shown, the solution of the present invention utilizes the reverse isolation characteristic of the amplifier, deletes the two switch selection circuits on the RX receiving channel, and replaces them with an amplifier and a 0 / 20dB attenuator, thereby reducing the local oscillator leakage by increasing the reverse isolation.

[0021] In order to suppress the local oscillator leakage on the Rx path, considering that the isolation between the transceiver channels cannot be optimized at present due to the fact that a single RF transceiver chip contains multiple channels, when the transmitter outputs a low-power signal, the isolation between the transceiver channels of the RF transceiver chip is general, and the local oscillator will leak into the Rx path. At this time, it is necessary to suppress the local oscillator leakage on the Rx path. This solution uses the reverse isolation characteristics of the amplifier to increase the reverse isolation on the Rx path by adding an amplifier and a 0 / 20dB attenuator, thereby reducing the local oscillator leakage.

[0022] Due to the reverse isolation characteristics of the amplifier, the local oscillator leakage power can be attenuated by at least 20dB each time it passes through an amplifier. When all three amplifiers are working, the local oscillator leakage power can be attenuated by at least 60dB. In order to avoid affecting the power dynamics of RX, the solution in the present invention also adds two 0 / 20dB attenuators. Since the amplifier gain used in the transceiver channel is about 20dB, the attenuation value of the 0 / 20dB attenuator can replace the switch selection circuit for power adjustment. When the amplifier turns on the attenuator to attenuate 20dB, it is equivalent to the received signal power not changing. When the amplifier turns on the attenuator without attenuation, it is equivalent to the received signal power amplification of 20dB. At the same time, when the 0 / 20dB attenuator attenuates 20dB, the leakage power will continue to attenuate. When both attenuators are working normally, the local oscillator leakage power can at least be attenuated by another 40dB, so that the local oscillator leakage output from the Rx port can be suppressed small enough and will not have a significant impact on the signal quality.

[0023] Compared with the original solution, the solution provided by the present invention has two amplifiers with reverse isolation characteristics and two 0 / 20dB attenuators. Each amplifier and 0 / 20dB attenuator replaces the switch selection circuit on the RX receiving channel in the conventional solution. Since the amplifier gain is about 20dB, when the attenuator attenuates by 20dB, the amplifier and the 20dB attenuator are used together, which is equivalent to the switch pointing to the amplifier path in the original solution; when the attenuator is not attenuated, only the amplifier works, which is equivalent to the switch pointing to the amplifier path in the original solution. The power of the Rx input signal is adjusted by the common use of the amplifier and the 0 / 20dB attenuator. The two groups of amplifiers and 0 / 20dB attenuators make the channel power adjustable range large enough to meet the requirements of a large dynamic range of power. In actual measurements, when the transmitter outputs a low-power signal under the conventional solution, the Rx local oscillator leakage power is about -80dBm, while under the same situation, in the circuit of the present invention, the Rx local oscillator leakage power is less than -160dBm. The use of the present invention solves the problem of local oscillator leakage at low power.

[0024] Compared with the conventional large dynamic local oscillator leakage suppression circuit technical solution in the prior art, the conventional technical solution is to suppress the local oscillator leakage in the transmitting channel through the channel estimation method or IQ pre-DC offset compensation, while the technical solution of the present invention is mainly to suppress the local oscillator leakage that leaks to the receiving channel due to the general isolation between the channels of the transceiver chip. The reverse isolation characteristics of the amplifier and the 0 / 20dB attenuator are used in combination to meet the requirements of the large dynamic range of the receiving channel power without affecting the normal input of the receiving channel signal, and the multi-stage attenuation of the local oscillator leakage is achieved through a simple circuit, thereby ensuring the quality of the signal.

[0025] The specific implementation scheme of this embodiment can refer to the relevant description in the above embodiment, which will not be repeated here.

[0026] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0027] It should be noted that, in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0028] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0029] The large dynamic local oscillator leakage suppression circuit system of the present invention greatly suppresses the local oscillator leakage on the Rx path when the transmitter outputs low power, thereby improving the signal quality. The present invention avoids affecting the power dynamics of the RX and reduces the complexity of the circuit.

[0030] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it is apparent that various modifications and variations may be made without departing from the spirit and scope of the present invention. Therefore, the specification and drawings should be regarded as illustrative rather than restrictive.

Claims

1. A large dynamic local oscillator leakage suppression circuit system, characterized in that: The system includes an RX receiving channel, which includes a first switch selection circuit, a 0 / 20dB attenuator and an amplifier. The first switch selection circuit, the 0 / 20dB attenuator and the amplifier are connected between a transmitter and a radio frequency transceiver chip, and the first switch selection circuit, the 0 / 20dB attenuator and the amplifier are connected in sequence.

2. The large dynamic local oscillator leakage suppression circuit system according to claim 1, characterized in that: The 0 / 20dB attenuator includes a first 0 / 20dB attenuator and a second 0 / 20dB attenuator, the amplifier includes a first amplifier and a second amplifier, the input end of the first 0 / 20dB attenuator is connected to the negative pole of the amplifier in the first switch selection circuit, the output end of the first 0 / 20dB attenuator is connected to the positive pole of the first amplifier, the negative pole of the first amplifier is connected to the second 0 / 20dB attenuator, and the positive pole of the second amplifier is connected to the second 0 / 20dB attenuator.

3. The large dynamic local oscillator leakage suppression circuit system according to claim 2, characterized in that: The 0 / 20dB attenuator is used to select 20dB attenuation or no attenuation.

4. The large dynamic local oscillator leakage suppression circuit system according to claim 1, characterized in that: The system also includes a TX transmission channel, which includes three switch selection circuits and a 2×20 attenuator, which are connected in sequence, and which are connected between the RF transceiver chip and the transmitter, and which are connected in sequence.

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