Digital phase shifter

Abstract

The embodiment of the invention discloses a digital phase shifter comprising a logic control circuit, at least four current digital-to-analog converters, at least four amplifiers and a vector summation circuit. The logic control circuit generates four N-bit digital phase shifting control signals according to (N+2)-bit digital control source signals to be respectively inputted to the four current digital-to-analog converters. The four current digital-to-analog converters are respectively connected in series with the four amplifiers so as to realize selection and amplification of four orthogonal input signals. The vector summation circuit synthesizes the amplification signals outputted by the four amplifiers so as to obtain the signals of which the phase can be shifted within the range of 360 degrees. The digital phase shifter is simple in circuit structure without additional arrangement of a phase shifting switching circuit so that noise can be reduced and the phase error / amplitude error can be improved; the circuit area is small and the chip cost can be reduced; and the phase shifting accuracy is high, and the accuracy value of the digital phase shifter can be adjusted by changing the total bits of the digital control source signals and the accuracy of the current digital-to-analog converters so as to meet different phase shifter design requirements.

Description

technical field [0001] The present application relates to the technical field of phase shifters, in particular to a digital phase shifter. Background technique [0002] In a wireless transceiver system, an ideal isotropic antenna transmits RF signals uniformly in all directions. However, a large amount of energy in the transmitted signal is not received by the receiving antenna, resulting in lower received signal power and greater spatial transmission power loss. Beamforming technology can solve this problem by creating directional antenna beams. Active phased array transceiver system is a kind of beamforming technology. figure 1 In the active phased array transceiver system shown, the antennas are arranged in a straight line at equal intervals (d) to form an array, and the phase difference of the input RF signals of adjacent antennas is α (that is, the delay ΔT), so the beam angle θ is determined by the following formula : [0003] Where λ is the carrier f of the tran...

AI Technical Summary

Problems solved by technology

Among them, the passive phase shifter uses on-chip integrated inductors and other components, resulting in a large circuit area, which is not suitable for small wireless communication devices; and high precision requirements

The circuit of the existing active phase shifter is complicated, which is not conducive to improving the phase shifting accuracy; moreover, the commonly used RF path series switch for quadrant switching is easy to introduce noise signals, worsen the phase error and amplitude error, and increase the insertion loss; although its It has a calibration circuit, but the phase shifting accuracy does not improve much after calibration (the phase shifting accuracy of an active phase shifter with a precision of 4-bit can only be improved by 1 bit after calibration)

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