Bias matcher matched with quadrature modulator

Abstract

The invention belongs to a bias matcher matched with a quadrature modulator, which comprises a blocking circuit, an alternating current (AC) matching interface circuit, a direct current (DC) bias circuit, two pairs of differential AC voltage input ports and two pairs of corresponding output ports. As a voltage division circuit shared by DC bias unit circuits is arranged between a DC power supply and a grounding end, and all blocking capacitors are re-arranged at the input ends of AC power supplies of the corresponding bias matching circuits, a grounding resistor in the voltage division circuit no longer has the function of a biasing resistor, while a corresponding AC matching resistor has the function of the biasing resistor respectively. Therefore, the bias matcher matched with the quadrature modulator is characterized in that: the circuit structure and the production process are simple, the requirement on performance consistency of the elements such as the resistor, the capacitor and the like is low, the consistency of performance parameters between the bias matching unit circuits and the matching between the quadrature modulators are high, the anti-interference capability of a signal is effectively improved, the spectrum distortion of the signal is inhibited; and the bias matcher can be industrially produced on a large scale, the production efficiency is high and the cost is low.

Description

technical field [0001] The invention belongs to a bias matcher in a communication device, in particular to a bias matcher used with a quadrature modulator, the matcher is connected to the differential input terminals of the I and Q two-way mixers The connection ensures the balance of the four inputs and effectively suppresses the spectral distortion of the signal. Background technique [0002] In the quadrature modulator, the I and Q two-way mixers have four differential signal input ports (IBBP, IBBN, QBBP and QBBN ports), and each port needs to pass through a DC bias circuit and an AC matching interface circuit. The included bias matching circuit provides DC bias voltage and realizes the maximum input power. Each circuit in a traditional bias matcher includes an AC matching interface unit circuit composed of a grounding resistor and an AC input wire, a grounding resistor (grounding circuit) and a (connected) DC power resistor (power supply circuit) and its A DC bias uni...

AI Technical Summary

Problems solved by technology

However, in production practice, the error of the marked parameter value and the actual (measured) parameter value of the components such as resistors and capacitors provided in production practice is generally within ±5-10%, even if the best resistors and capacitors are selected and welded, When the debugging is very good, it is difficult to ensure that the resistance error between each pair of ports is within the range of ±5%, and the suppression degree of the local oscillator can only reach about 15db, which is far from being able to exert quadrature modulation. The local vibration suppression degree of the device should be ≥ 30db ideal performance

Among them, due to the many resistive components involved in the DC bias circuit, the consistency of performance is more difficult to meet the requirements; -id="HSA00000331818500012" img-title="Figure 2">Figure 2, R3 and R2 form a voltage divider circuit, and R2 also acts as a bias resistor. It is necessary to coordinate each differential The DC bias voltage of the signal input port itself; at the same time, it is necessary to ensure that the DC bias voltage between the four differential signal input ports is highly consistent, so it is extremely difficult to debug. The voltage difference between the bias voltages input by the matching circuit is extremely sensitive (every difference of 1mV, its local oscillation suppression degree is reduced by 1-2db, and each resistance value in each group of corresponding resistors differs by 1%, its bias voltage There will be a difference of about 12mV between them)

Therefore, this type of bias matcher has poor consistency in the performance of each bias matching circuit, poor manufacturability in the production process, difficult debugging, and poor matching with the quadrature modulator during use, which greatly limits the performance of the quadrature modulator performance and reduce the anti-interference ability of the signal and other defects; if the resistance and capacitance used in each set of bias matchers are assembled with actual measurement and matching, although the matching can be improved to a certain extent and to a certain extent Promote the performance of the quadrature modulator, but there are disadvantages such as difficulty in industrial production and a significant increase in production costs

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