CN106374880A

CN106374880A - Self-adaptive bandwidth filter based on switch capacitor

Info

Publication number: CN106374880A
Application number: CN201610775227.2A
Authority: CN
Inventors: 周峰; 汤泽波
Original assignee: Anhui Safe Electronics Co Ltd
Current assignee: Anhui Safe Electronics Co Ltd
Priority date: 2016-08-31
Filing date: 2016-08-31
Publication date: 2017-02-01

Abstract

The invention discloses a self-adaptive bandwidth filter based on a switch capacitor. The self-adaptive bandwidth filter comprises an analogue processing component and a digital control component; the analogue processing component is composed of a low-pass and band-pass multiplexing filter and a hysteresis comparator; the digital control component is composed of a logic controller, a counter and a clock selection bar; the low-pass and band-pass multiplexing filter is connected to the hysteresis comparator, the logic controller and the clock selection bar; the hysteresis comparator is connected with the counter; the counter is connected with the logic controller; and the logic controller is also connected with the clock selection bar. According to the self-adaptive bandwidth filter based on the switch capacitor provided by the invention, the bandwidth of the filter can be self-adaptively adjusted by detection of the frequency of an input signal under a condition that the frequency of the input signal or the signal frequency is uncertain or often changed; and thus, low-pass or band-pass filtering processing of the input signal, the frequency of which is uncertain or often changed, can be realized effectively.

Description

A kind of bandwidth self-adaption wave filter based on switching capacity

Technical field

The present invention relates to a kind of wave filter, more particularly, to a kind of bandwidth self-adaption wave filter based on switching capacity.

Background technology

Wave filter is one of most important component in analog circuit, the application pole in telecommunication apparatus and all kinds of control system For extensive.The quality of one product, is often depending on this product circuit median filter performance.

At present, integrated circuit wave filter is mainly using continuous time filter and SCF both.Wherein, Continuous time, analog filter was applicable to higher frequency, and its transfer function coefficient to be determined by mutual conductance and capacitance, Precision and the linearity are bad, and zero pole point controls complexity, big by technogenic influence；And SCF transfer function depends on electricity Hold ratio, transfer function high precision unrelated with technological parameter, and realize big resistance with smaller capacitive, save area, beneficial to integrated, Meet high integration, in high precision, the design direction such as low-power consumption.Configurable multi-mode filter, with respect to general filter, having can With by controlling the advantage making same circuit be operated in the different modes such as low pass, band logical.

Existing SCF, mostly changes the sample clock frequency of wave filter by the method for programming, from And change cut-off frequency or the mid frequency of wave filter, but in the face of frequency input signal is in the feelings of interior real-time change in a big way Condition, the programmed method based on manual operation cannot meet the requirement to filtering for the signal.

Content of the invention

For the deficiencies in the prior art, it is an object of the invention to provide a kind of bandwidth self-adaption filter based on switching capacity Ripple device, overcomes existing SCF, and its programmed method based on manual operation cannot meet signal to be wanted to filtering The deficiency asked.

In order to achieve the above object, the present invention employs the following technical solutions:

A kind of bandwidth self-adaption wave filter based on switching capacity, described wave filter includes simulation process component and digital control structure Part, described simulation process component includes low pass band logical multiplex filter and hysteresis comparator, and described digital control component includes patrolling Collect controller, enumerator and clock selecting bar, described low pass band logical multiplex filter is connected with hysteresis comparator, logic controller With clock selecting bar, described hysteresis comparator is connected with enumerator, and described enumerator is connected with logic controller, described logic control Device processed is also connected with clock selecting bar.

Described clock selecting bar clock selecting bar is one eight select one MUX.

The invention has the beneficial effects as follows: in the case that frequency input signal or signal frequency do not know or often change, Filter bandwidht can be adaptively adjusted by the detection to frequency input signal, have effectively achieved and frequency is not known Or the input signal that changes carries out low pass or bandpass filtering treatment often.

Brief description

Fig. 1 is a kind of structured flowchart based on switching capacity bandwidth self-adaption wave filter of the present invention.

In figure, 1- simulation process component, 11- low pass band logical multiplex filter, the digital control component of 2-, 21- logic control Device, 22- enumerator, 23- clock selecting bar.

Specific embodiment

The invention will be further described to combine accompanying drawing below by embodiment.

A kind of bandwidth self-adaption wave filter based on switching capacity, as shown in figure 1, include simulation process component 1 and numeral Control member 2, described simulation process component 1 is made up of low pass band logical multiplex filter 11 and hysteresis comparator 12, described numeral Control member 2 is made up of logic controller 21, enumerator 22 and clock selecting bar 23, and described low pass band logical multiplex filter 11 is even It is connected to hysteresis comparator 12, logic controller 21 and clock selecting bar 23, described hysteresis comparator 12 is connected with enumerator 22, institute State enumerator 22 to be connected with logic controller 21, described logic controller 21 is also connected with clock selecting bar 23.

Hysteresis comparator 12 can carry out the quantization of denoising to the signal of low pass band logical multiplex filter output, obtains energy Enough reflect the square-wave signal of basic frequency of signal rate.Clock selecting bar 23 is one eight select one MUX, clock to be selected is conspicuous Hereby it is set as: 80khz, 100khz, 125khz, 160khz, 200khz, 250khz, 320khz and 400khz.

SCF and general active rc wave filter differ primarily in that it with a switching capacity come etc. Effect ground substitutes the big resistance being difficult in chip accurately realize.SCF is provided that more accurate cut-off frequency, and And it is affected all very littles by temperature and technique, is capable of matched.

Enumerator is one and carries out inverse with 800khz clock, makees the 8-digit of reset signal with square-wave signal rising edge Device.Hysteresis comparator can carry out the quantization of denoising to the signal of low pass band logical multiplex filter output, obtains reflecting The square-wave signal of basic frequency of signal rate.

Also it is not detected at when square-wave signal rises through the long period (200 μ s), wave filter active state is to cut Only frequency is the low pass filter of 40khz, and waits square-wave signal rising edge in this state；When detecting on square-wave signal Rise along when, then counter results are refreshed, according to new counter results, if ongoing frequency be less than 6.25khz, wave filter It is changed into the low pass filter that a cut-off frequency is 40khz；On the contrary, if ongoing frequency is less than 6.25khz, according to current Specific frequency, automatically selects the most suitable band filter of mid frequency；The band filter energy that eight sampling clocks produce Enough complete frequency ranges covering 6.25～50khz.Further, since wave filter different different phase places can be caused using clock frequency Time delay, so after the present invention design each sampling clock of wave filter changes, the state of wave filter at least keeps two signal periods.

Claims

1. a kind of bandwidth self-adaption wave filter based on switching capacity it is characterised in that: described wave filter includes simulation process structure Part (1) and digital control member (2), described simulation process component (1) includes low pass band logical multiplex filter (11) and sluggish ratio Compared with device (12), described digital control component (2) includes logic controller (21), enumerator (22) and clock selecting bar (23), institute State low pass band logical multiplex filter (11) and be connected with hysteresis comparator (12), logic controller (21) and clock selecting bar (23), Described hysteresis comparator (12) is connected with enumerator (22), and described enumerator (22) is connected with logic controller (21), described patrols Collect controller (21) to be also connected with clock selecting bar (23).

2. the bandwidth self-adaption wave filter based on switching capacity according to claim 1 it is characterised in that: the choosing of described clock Select bar clock selecting bar (23) to be one eight select one MUX.