Digital power amplifier supporting broadband modulation signals

Abstract

The invention belongs to the technical field of wireless communication, and particularly relates to a digital power amplifier supporting broadband modulation signals. Comprising a digital power amplifier array and a passive network, the digital power amplifier array is composed of a plurality of units, the input end of the digital power amplifier array is connected with input signals, and the output end is connected with the passive network; the input signals are divided into a plurality of groups, each group of signals consists of a flag bit signal, an amplitude signal and a local oscillator signal, each group of signals is respectively sent into each unit in the digital power amplifier array, and the local oscillator phase selection operation is completed in the unit and the local oscillator signal through a local oscillator phase selection circuit; the synchronism between the phase signal and the amplitude signal is ensured; in each unit, one of the flag bit signals is selected from the differential local oscillator signals to be transmitted backwards for output, and meanwhile, the amplitude signals are subjected to delay synchronization through the identical dummy circuits. The invention has the characteristics of supporting high bandwidth and high linearity, and is suitable for wireless communication application with wide signal bandwidth such as Wi-Fi 7, 5G and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of wireless communications, and in particular relates to a digital power amplifier supporting broadband modulation signals. Background Art

[0002] The rapid development of wireless communication technology has greatly improved productivity and quality of life. Currently, smartphones and tablets that support 2G / 3G / 4G / 5G mobile communications, wireless local area networks (WLAN), Bluetooth and other applications have become standard configurations in people's work and life. As the user experience of electronic devices improves, people's demand for data transmission rates is getting higher and higher, and wireless communications are developing towards wider modulation signals to support higher data rates. For example, the channel bandwidth of the Wi-Fi 6 protocol is increased to 160MHz, while the channel bandwidth of the Wi-Fi 7 protocol is increased to 320MHz. Wider modulation signal bandwidth increases the difficulty of designing circuits such as transmitters in wireless communications. Generally, in scenarios with wider modulation signal bandwidths, the requirements for internal circuit signal synchronization and output linearity are significantly increased.

[0003] The input signals of the digital power amplifier include the flag signal, the amplitude signal and the local oscillator signal. The flag signal and the amplitude signal are both baseband signals. The flag signal carries phase information, and the amplitude signal carries amplitude information. Therefore, the synchronization between the flag signal and the amplitude signal is very important for the output linearity of the digital power amplifier. However, since the roles of the flag signal and the amplitude signal in the digital power amplifier are not exactly the same, the links they go through are usually different, resulting in a certain degree of asynchrony, which will significantly deteriorate the linearity in the broadband modulation signal scenario. Figure 1 The figure shows the linearity variation of an orthogonal digital power amplifier model under dynamic signals of different baseband bandwidths (20 / 50 / 100 / 200MHz). The horizontal axis is the delay between the marker signal and the amplitude signal. The greater the delay, the worse the synchronization. The indicator for evaluating linearity here is the spurious-free dynamic range (SFDR) of the output spectrum of the digital power amplifier model. The smaller the SFDR, the better the corresponding linearity performance. It can be seen that the wider the baseband signal bandwidth, the higher the requirement for synchronization between the marker signal and the amplitude signal.

[0004] At present, the academic and industrial communities at home and abroad usually follow the practice of setting up a local oscillator phase selection module separately at the top level in terms of architecture solutions. For the synchronization problem between the flag signal and the amplitude signal, some solutions are to add control words and delay chains at the top level of the system to specifically control the delay of the flag signal, which is used to optimize the synchronization between the phase information carried by the flag signal and the amplitude information carried by the amplitude signal in the circuit. However, this requires a certain number of bits of external control coding, which will cause higher system complexity. At the same time, the quality of synchronization optimization is also limited by the resolution of the control coding. Summary of the invention

[0005] In view of the above problems, the present invention aims to provide a digital power amplifier supporting broadband modulation signals with low system complexity.

[0006] The present invention provides a digital power amplifier supporting broadband modulation signals, comprising a digital power amplifier array and a passive network. The digital power amplifier array is composed of a plurality of units, the input end of the digital power amplifier array is connected to the input signal, and the output end is connected to the passive network; the input signal is divided into a plurality of groups, each group of signals is composed of a flag signal (SIGN), an amplitude signal (BB) and a local oscillator signal (LO), each group of signals is respectively sent to each unit in the digital power amplifier array, and the local oscillator signal (LO) passes through a local oscillator phase selection circuit inside the unit to complete a local oscillator phase selection operation, thereby ensuring the synchronization between the phase signal and the amplitude signal; in each unit, the flag signal selects one of the differential local oscillator signals to be transmitted backward for output, and the amplitude signal is synchronized with a completely identical dummy circuit for delay.

[0007] In the present invention, the differential local oscillator signal is realized by inputting a differential local oscillator signal, or inputting a single-ended local oscillator signal, and generating a differential local oscillator signal internally through a single-turn differential circuit.

[0008] The beneficial effect of the present invention is that compared with the traditional architecture solution, the digital power amplifier supporting broadband modulation signals of the present invention can better ensure the synchronization between the flag signal and the amplitude signal by embedding the path of the flag signal into each unit, which is completely consistent with the path of the amplitude signal, while avoiding adding additional control words in the system and reducing the system complexity. The digital power amplifier architecture proposed by the present invention has the characteristics of good synchronization performance and low system complexity, and is suitable for wireless communication applications with wide modulation signal bandwidth such as WLAN and 5G. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1The figure shows the linearity change of an orthogonal digital power amplifier model under dynamic signals with different baseband bandwidths (20 / 50 / 100 / 200MHz). The horizontal axis is the delay between the flag signal and the amplitude signal. The larger the delay, the worse the synchronization.

[0010] Figure 2 :Example 1: Figure of a digital power amplifier supporting broadband modulation signals.

[0011] Figure 3 : Example 2 is an example of an implementation method of a digital power amplifier that supports broadband modulated signals. DETAILED DESCRIPTION

[0012] The present invention is further described below by way of embodiments in conjunction with the accompanying drawings.

[0013] Example 1: Figure 2 As shown, in the digital power amplifier proposed by the present invention, the flag signal (SIGN) in the input signal is directly sent to each unit in the digital power amplifier array together with the amplitude signal (BB) and the local oscillator signal (LO), and one of the signals is selected inside the unit and the differential local oscillator signal to be transmitted backward for output, and the amplitude signal is delayed and synchronized through a completely identical dummy circuit, which can effectively ensure the synchronization between the phase information and the amplitude information. Example

[0014] The digital power amplifier can be implemented in a variety of ways. Figure 3 A gate circuit-based implementation method is given. After the input signals SIGN, BB, and LO enter each unit circuit, the LO signal is converted from single-ended to differential to obtain a differential LO signal, which is then selected with the SIGN signal through three NAND gates. At the same time, the BB signal is delayed through a completely consistent NAND gate circuit, so that the phase information carried by the SIGN signal and the amplitude information carried by the BB signal are completely synchronized.

[0015] Therefore, the present invention proposes a digital power amplifier that supports broadband modulation signals with low system complexity. By embedding the path of the flag signal into each unit and making it completely consistent with the path of the amplitude signal, the synchronization between the flag signal and the amplitude signal is better guaranteed, while avoiding adding additional control words in the system and reducing system complexity. The digital power amplifier architecture proposed in the present invention has the characteristics of good synchronization performance and low system complexity, and is suitable for wireless communication applications with wide modulation signal bandwidth such as WLAN and 5G.

Claims

1. A digital power amplifier supporting broadband modulation signals, characterized in that: The invention comprises a digital power amplifier array and a passive network. The digital power amplifier array is composed of a plurality of units. The input end of the digital power amplifier array is connected to the input signal, and the output end is connected to the passive network. The input signal is divided into a plurality of groups. Each group of signals is composed of a flag signal (SIGN), an amplitude signal (BB) and a local oscillator signal (LO). Each group of signals is respectively sent to each unit in the digital power amplifier array. The local oscillator phase selection operation is completed inside the unit and the local oscillator signal (LO) passes through a local oscillator phase selection circuit to ensure the synchronization between the phase signal and the amplitude signal. In each unit, the flag signal selects one of the differential local oscillator signals to be transmitted backward for output, and the amplitude signal is synchronized with the delay through a completely identical dummy circuit.

2. The digital power amplifier for broadband modulated signals according to claim 1, characterized in that: The differential local oscillator signal is realized by inputting a differential local oscillator signal, or inputting a single-ended local oscillator signal, and generating a differential local oscillator signal internally through a single-turn differential circuit.

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