阅读说明：本技术 一种可重构谐波抑制复数滤波器 (Reconfigurable harmonic suppression complex filter ) 是由 王科平 陈瑞 宗培胜 于 2019-09-26 设计创作，主要内容包括：本发明公开了一种可重构谐波抑制复数滤波器,包括2N个电压放大器、N个结构相同的多相位复数滤波器;其中N为大于等于2的正整数。2N个电压放大器用来实现对相邻两级多相位复数滤波器之间的隔离,以防止相邻滤波器互为彼此负载,从而恶化滤波器的滤波性能。N个复数滤波器用来对输入的中频信号进行选择和滤波。其中某一级复数滤波器的基波频率决定了整体滤波器的中心频率,其余N-1级复数滤波器用来增加整体滤波器的谐波抑制及带内平坦度性能。本实施例的可重构谐波抑制复数滤波器基于差分N通道滤波器的原理,与现有的模拟基带滤波器相比,具有显著的功耗和面积性能。(The invention discloses a reconfigurable harmonic suppression complex filter which comprises 2N voltage amplifiers and N multiphase complex filters with the same structure, wherein N is a positive integer greater than or equal to 2. The 2N voltage amplifiers are used for realizing the isolation between the adjacent two stages of multiphase complex filters so as to prevent the adjacent filters from mutually loading each other, thereby deteriorating the filtering performance of the filters. The N complex filters are used to select and filter the input intermediate frequency signal. The fundamental frequency of one stage of complex filter determines the center frequency of the whole filter, and the rest N-1 stages of complex filters are used for increasing the harmonic suppression and in-band flatness performance of the whole filter. The reconfigurable harmonic suppression complex filter of the embodiment is based on the principle of a differential N-channel filter, and has remarkable power consumption and area performance compared with the existing analog baseband filter.)

1. A reconfigurable harmonic rejection complex filter, characterized by: the multi-phase clock signal generating circuit comprises N multi-phase clock complex filters with different frequencies and 2N voltage amplifiers, wherein N is a positive integer greater than or equal to 2; the voltage amplifier is used for carrying out voltage isolation on adjacent complex filters; n complex filters are used for selecting and filtering the input intermediate frequency signals; the fundamental frequency of one stage of complex filter determines the center frequency of the overall filter, and the rest N-1 stages of complex filters are used for increasing the harmonic suppression and in-band flatness performance of the overall filter.

2. The reconfigurable harmonic rejection complex filter of claim 1, wherein the I and Q paths are generated by applying a direct input voltage amplifier and a 90 ° phase shifted input voltage amplifier to the input differential IF signal.

3. A harmonic rejection complex filter as in claim 2 wherein: wherein I_N、I_P、Q_N、Q_PRespectively representing the phases of the input intermediate frequency signals as 0 DEG, 180 DEG, 90 DEG and 270 deg.

4. According to the claimsThe reconfigurable harmonic suppression complex filter of claim 1 is characterized in that: the input intermediate frequency signal adopts a differential quadrature path, and the differential and quadrature paths share a baseband capacitor C_BB。

5. A reconfigurable harmonic rejection complex filter as claimed in claim 1 wherein: n multi-phase clock complex filters with different frequencies are adopted, corresponding to N different 1, 3, 5 and 7 … harmonic frequencies, the 1, 3, 5 and 7 … harmonic frequencies of each stage of filter are mutually overlapped, and therefore better filter performance is obtained.

6. A reconfigurable harmonic rejection complex filter as claimed in claim 1 wherein: the voltage amplifier adopts a programmable gain amplifier.

Technical Field

The invention belongs to the technical field of circuits and systems, and particularly relates to a reconfigurable harmonic suppression complex filter.

Background

The wireless receiver has a wide application in the field of communications, and generally adopts a zero or low intermediate frequency structure. The channel selection and image rejection are usually performed by analog baseband filters.

The analog baseband filter of the above type is composed of a linear capacitor and a resistor, and an active RC low-pass filter or an active complex band-pass filter is usually used to process an intermediate frequency signal, but the structure of the active filter using an operational amplifier consumes a large power and occupies a large chip area.

Time-continuous N-channel filters were proposed in the 60's of the 20 th century, mainly for kHz operating frequencies. With the continued expansion of CMOS technology, N-channel filters can operate at RF frequencies in the television band even above 1 GHz. Since the N-channel filter is driven by N different external clocks, its on and off characteristics are ideal, and the static power consumption is substantially 0. But the single-stage N-channel filter has the defects of high harmonic peak value and low in-band flatness.

Therefore, the analog baseband filter in the prior art has the defects of large power consumption and large circuit area; the existing single-stage N-channel filter has the defects of high harmonic peak value and low in-band flatness.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a reconfigurable harmonic suppression complex filter, which adopts N multiphase clock complex filters with different frequencies, and can realize harmonic suppression, reduce circuit power consumption, reduce circuit area and improve the flatness performance of the whole passband of the filter in an analog baseband filter.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a reconfigurable harmonic suppression complex filter comprises N multiphase clock complex filters with different frequencies and 2N voltage amplifiers, wherein N is a positive integer greater than or equal to 2. The N multiphase clock complex filters with different frequencies are used for replacing an analog baseband filter of a traditional receiver link and filtering and channel selection of low and intermediate frequency signals in a wireless receiver link; the voltage amplifier is used for carrying out voltage isolation on adjacent complex filters; n complex filters are used for selecting and filtering the input intermediate frequency signals; the fundamental frequency of one stage of complex filter determines the center frequency of the overall filter, and the rest N-1 stages of complex filters are used for increasing the harmonic suppression and in-band flatness performance of the overall filter.

The reconfigurable harmonic suppression complex filter is characterized in that the multi-phase clock frequency of the complex filter can be adjusted so as to adjust the center frequency of the filter, namely the frequency of a required signal; the harmonic suppression of one reconfigurable harmonic suppression complex filter is to suppress odd and even harmonics of clock frequency, so that a better Q value of the filter, namely the overall passband performance of the filter can be obtained.

The invention adopts the voltage amplifier to isolate N multiphase clock complex filters with different frequencies, so that the filter characteristics between two adjacent filters are not influenced by the loads of the two filters.

The invention further improves that: the input intermediate frequency signal adopts a differential quadrature path, and the differential and quadrature paths share a baseband capacitor C_BB。

The invention is further improved in that: n multi-phase clock complex filters with different frequencies are adopted, corresponding to N different 1, 3, 5 and 7 … harmonic frequencies, the 1, 3, 5 and 7 … harmonic frequencies of each stage of filter are mutually overlapped, and therefore better filter performance is obtained.

The invention is further improved in that: the voltage amplifier adopts a programmable gain amplifier.

The central signal frequency of the invention can reach the image rejection ratio of more than 45dB, and has good harmonic suppression performance, namely, the sideband of the filter has good passband characteristic; a passive double-balanced frequency mixing structure is adopted, and as the on-off characteristic of an external clock is ideal, the static power consumption of each filter is almost 0; therefore, the overall power consumption of the filter can reach the micro watt level.

Has the advantages that:

the invention has the following advantages:

1. the static power consumption of the N complex filters is very small, and the power consumption of the whole filter can be reduced to a microwatt level.

2. The filter has a harmonic suppression function, high-Q passband characteristics and a small circuit area.

Drawings

Fig. 1 is a schematic structural diagram of a reconfigurable harmonic suppression complex filter provided by an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a 3-stage reconfigurable harmonic suppression complex filter provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of a voltage amplifier circuit;

FIG. 4 is a schematic diagram of a single stage complex filter circuit (using an 8-phase clock as an example);

fig. 5 is a schematic diagram illustrating an operating principle of a reconfigurable harmonic suppression complex filter according to an embodiment of the present invention;

fig. 6 is a schematic diagram of the operation of a Programmable Gain Amplifier (PGA) instead of a voltage amplifier.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.