CN108768329A - Double AGC systems - Google Patents
Double AGC systems Download PDFInfo
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- CN108768329A CN108768329A CN201810812700.9A CN201810812700A CN108768329A CN 108768329 A CN108768329 A CN 108768329A CN 201810812700 A CN201810812700 A CN 201810812700A CN 108768329 A CN108768329 A CN 108768329A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/3005—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G2201/00—Indexing scheme relating to subclass H03G
- H03G2201/40—Combined gain and bias control
Abstract
The invention discloses a kind of double AGC systems, including：Zero passage detection unit；Gain linearization unit, in digital input signals zero passage, finding the first gain adjustment value and the second gain adjustment value of linearisation in linear look-up table according to automatic gain stairstep signal；Output gain adjustment unit, for obtaining digital output signal after multiplying and saturation arithmetic processing according to digital input signals and the first gain adjustment value；Input gain adjustment unit, for according to digital input signals and the second gain adjustment value, after multiplying and saturation arithmetic processing, obtaining input gain adjustment signal；Selecting unit, the mode signal for being received according to mode signal input terminal, selectivity exports digital output signal or input gain adjusts signal；Automatic gain control unit generates automatic gain stairstep signal for the output signal according to selection signal output end.The invention can avoid the risks of digital input signals truncation and signal overcompression for implementation.
Description
Technical field
The present invention relates to automatic growth control field, more particularly to a kind of double AGC systems.
Background technology
In the field of Audio Signal Processing, for the automatic growth control of digital audio and video signals, have all the time quite
More research does not damage loudspeaker, and the not unsweet sound phenomenon of sound, in digital sound to make audio signal after amplification
In frequency processing, automatic growth control (automatic gain control, AGC) technology is applied always extensively.It is for example existing
In Fig. 1 in technology：Directly output signal has been used to check whether gain is excessive, and to adjust the gain of input signal.
In Fig. 2 in the prior art：When checking whether gain adjusts, takes and come to signal gain in signal zero passage
Adjustment, the shortcomings that too early change of voice of the sound in Fig. 1 can be effectively prevent.
Although however, Fig. 2 by when signal zero passage come to signal gain adjust, the sound that can be effectively prevent in Fig. 1
The shortcomings that too early change of voice, but the strategy of its AGC is too simple, is susceptible to digital input signals truncation and signal overcompression
Risk.
Invention content
In view of this, the present invention is intended to provide a kind of double AGC systems, over-pressed to avoid digital input signals truncation and signal
The risk of contracting.
Specifically, the present invention provides a kind of double AGC systems, including：
Zero passage detection unit, for detect digital input signals whether zero passage；
Gain linearization unit is used in the digital input signals zero passage, online according to automatic gain stairstep signal
The first gain adjustment value and the second gain adjustment value of linearisation are found in property look-up table；
Output gain adjustment unit, for according to the digital input signals and the first gain adjustment value, being transported by multiplication
It calculates with after saturation arithmetic processing, obtains digital output signal；
Input gain adjustment unit, for according to the digital input signals and the second gain adjustment value, being transported by multiplication
It calculates and after saturation arithmetic processing, obtains input gain adjustment signal；
Selecting unit, including：It is mode signal input terminal, defeated for receiving the first choice signal of the digital output signal
Enter end, adjust the second selection signal input terminal and selection signal output end of signal for receiving the input gain；It is described
The mode signal that selection signal output end is used to be received according to the mode signal input terminal, selectivity export the numeral output
Signal or the input gain adjust signal；
Automatic gain control unit generates the automatic increasing for the output signal according to the selection signal output end
Beneficial stairstep signal.
Further, double AGC systems further include：
Prevent big unit, for according to preset amplifying parameters, being amplified processing to the digital input signals, obtaining
The digital input signals of amplification；
The output gain adjustment unit includes the first multiplier and the first saturation arithmetic processor, first multiplier
The digital input signals of the amplification and the first product of the first gain adjustment value are calculated, the first saturation arithmetic processor is used
In carrying out saturation arithmetic processing to first product, the digital output signal is obtained；
The input gain adjustment unit includes the second multiplier and the second saturation arithmetic processor, second multiplier
The digital input signals of the amplification and the second product of the second gain adjustment value are calculated, the second saturation arithmetic processor is used
In carrying out saturation arithmetic processing to second product, the input gain adjustment signal is obtained.
Further, double AGC systems further include absolute value calculation unit, the input of the absolute value calculation unit
End connects the selection signal output end of the selecting unit；The output end of the absolute value calculation unit connects the automatic gain
The input terminal of control unit；
The automatic gain control unit is used for the output signal of the output end according to the absolute value calculation unit, raw
At the automatic gain stairstep signal.
Further, the automatic gain control unit includes：
Reset signal end, fast gain Enable Pin and slow gain Enable Pin；
Signal peak monitoring modular, for judging whether the input signal of the automatic gain control unit is more than preset
Quick AGC amplitude thresholds, at a slow speed AGC amplitude thresholds and AGC discharge amplitude threshold, and corresponding monitoring is generated according to judging result
Value, the monitor value include quick AGC amplitudes monitor value, at a slow speed AGC amplitudes monitor value and AGC release amplitude monitor values；
Major state machine, for according to preset fast gain count value, slow gain counter, holding gain count value
And the correspondence of various monitor values and the working condition of each automatic gain control unit, it determines in the corresponding monitor value
When working condition, and export current work state information and subsequent work status information；The working condition includes：To institute
Release (Release) state, the digital input signal that digital input signals are stated without Gain tuning carry out faster slower speed gain
Tracking (Attack) state of adjustment, holding (HOLD) shape for maintaining output of the digital input signals under fixed gain amplitude
State；
Fast gain counter, for according to the current work state information and subsequent work status information and in advance
If quick AGC adjust a step gain need duration, counted, obtain the fast gain count value；
Slow gain counter, for according to the current work state information and subsequent work status information and in advance
If AGC at a slow speed adjust a step gain need duration, counted, obtain the slow gain count value；
Gain counter is kept, for according to the current work state information and subsequent work status information and in advance
If holding AGC amplitudes when adjust a step gain needs duration, counted, obtain the holding gain count value；
Gain step by step modulating module, for according to the current work state information, subsequent work status information, quickly
Gain count value, slow gain counter, quick AGC amplitudes monitor value, at a slow speed AGC amplitudes monitor value and AGC discharge amplitude
Monitor value generates the automatic gain stairstep signal, and the automatic gain stairstep signal amplitude limit is in preset gain step by step modulating
Maximum value.
Further, the zero passage detection unit, including：
First delay time register, first end is for receiving the digital input signals, second end for receiving clock signal
And first output end；
Logic or non-operation module, first end is for receiving the digital input signals, second end for receiving described the
The signal and second output terminal of the output end of one delay time register；
Logic or computing module, first end are used to receive digital input signals detection knot minimum near positive value
Fruit, second end are for receiving digital input signals testing result minimum near negative value and third end for receiving
The output signal of the second output terminal, and the third output end for exporting zero passage detection signal.
Further, the gain linearization unit includes：
Adder, for be calculated gain that pre-set yield value is added with automatic gain stairstep signal and
Value；
Second delay time register, including：Data input pin for receiving the gain and value, clock signal input terminal end,
Enable Pin for receiving the zero passage detection signal and delayed data output end；
Selector, including：Enable Pin for receiving the zero passage detection signal, for receiving the gain and value
One selection input terminal, the second selection input terminal for connecting the delayed data output end, and selection output end, the choosing
Output end is selected for according to the zero passage detection signal, the gain and value or delayed data output to be received in selectivity output
The output signal at end；
First table look-up module, for finding linearisation in linear look-up table according to the output signal of the selection output end
The first gain adjustment value；
Second table look-up module, the second gain tune for finding linearisation in linear look-up table according to the gain and value
Section value.
Further, the gain linearization unit further includes：The input terminal of clipping module, the clipping module connects institute
The output end of adder is stated, the output end of the clipping module connects the data input pin of second delay time register.
Further, the entry condition of the release conditions includes：
The reset signal end receives reset signal, and the fast gain Enable Pin and slow gain Enable Pin are not received
To enable signal；Alternatively,
In hold mode, the signal peak monitoring modular can't detect the input letter of the automatic gain control unit
Number beyond the quick AGC amplitude thresholds, AGC amplitude thresholds and AGC discharge amplitude threshold at a slow speed, are keeping gain counter
Enter the release conditions after meter is full；
The condition that the release conditions enter tracking mode includes：The signal peak monitoring modular detects described automatic
The input signal of gain control unit AGC amplitude thresholds beyond the quick AGC amplitude thresholds or at a slow speed.
Further, the entry condition of the tracking mode includes：
The signal peak monitoring modular detects the input signal of the automatic gain control unit beyond described quick
AGC amplitude thresholds or at a slow speed AGC amplitude thresholds；
The condition that the tracking mode enters hold mode includes：
The input signal that the signal peak monitoring modular detects the automatic gain control unit is quick without departing from described
AGC amplitude thresholds and at a slow speed AGC amplitude thresholds.
Further, the entry condition of hold mode includes：
In the tracking mode, the signal peak monitoring modular detects the input letter of the automatic gain control unit
Number without departing from the quick AGC amplitude thresholds and at a slow speed AGC amplitude thresholds；
In the hold mode, the signal peak monitoring modular detects the input letter of the automatic gain control unit
Number beyond AGC discharge amplitude monitor value；
The hold mode enter the tracking mode condition include：
The signal peak monitoring modular can't detect the input signal of the automatic gain control unit beyond described fast
Fast AGC amplitude thresholds, at a slow speed AGC amplitude thresholds and AGC discharge amplitude threshold, and the holding gain counter counts are full.
Double AGC systems of the present invention, it is single by the way that output gain adjustment unit, input gain adjustment unit and selection is arranged
Member, the mode signal that selection signal output end is used to be received according to the mode signal input terminal, selectivity export the number
Output signal or the input gain adjust signal, thus on the judgement source to automatic gain control unit, by configuring choosing
The input gain adjustment signal after the digital output signal either pre-amplification after AGC is selected, not only for
On the application scenarios of AGC, there is more flexible selection, moreover it is possible to dynamic realtime adjustment be carried out to the amplitude of audio signal, to greatest extent
Retain primary sound and reduces the risk of signal truncation and signal overcompression.
Description of the drawings
It is incorporated into specification and the attached drawing of a part for constitution instruction shows the embodiment of the present invention, and with
Principle for explaining the present invention together is described.In the drawings, similar reference numeral is for indicating similar element.Under
Attached drawing in the description of face is some embodiments of the present invention, rather than whole embodiments.Those of ordinary skill in the art are come
It says, it without creative efforts, can be obtain other attached drawings according to these attached drawings.
Fig. 1 is the topological schematic diagram of the first existing AGC system；
Fig. 2 is the topological schematic diagram of existing second of AGC system；
Fig. 3 is a kind of topological schematic diagram of double AGC systems provided in an embodiment of the present invention；
Fig. 4 is a kind of structural schematic diagram of double AGC systems provided in an embodiment of the present invention；
Fig. 5 is quick AGC amplitude thresholds in a kind of double AGC systems provided in an embodiment of the present invention and AGC amplitudes at a slow speed
The waveform diagram of threshold value；
Fig. 6 is the structure chart of the automatic gain control unit in a kind of double AGC systems that bright embodiment provides.
The state transition diagram of major state machine in the automatic gain control unit that Fig. 7 is Fig. 6；
Fig. 8 is zero passage detection unit and gain linearization unit in a kind of double AGC systems provided in an embodiment of the present invention
Structural schematic diagram.
Fig. 9 is the schematic diagram of the saturation arithmetic in a kind of double AGC systems provided in an embodiment of the present invention.
Specific implementation mode
In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention
In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is
A part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, those of ordinary skill in the art
The every other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.It needs
Illustrate, in the absence of conflict, the features in the embodiments and the embodiments of the present application mutually can be combined arbitrarily.
The invention will now be described in detail with reference to the accompanying drawings implements the double AGC systems being related to.
Shown in Fig. 3-Fig. 4, a kind of double AGC systems provided in an embodiment of the present invention include：
Zero passage detection unit, for detect digital input signals whether zero passage；
Gain linearization unit is used in the digital input signals zero passage, online according to automatic gain stairstep signal
The first gain adjustment value and the second gain adjustment value of linearisation are found in property look-up table；
Output gain adjustment unit, for according to the digital input signals and the first gain adjustment value, being transported by multiplication
It calculates with after saturation arithmetic processing, obtains digital output signal；
Input gain adjustment unit, for according to the digital input signals and the second gain adjustment value, being transported by multiplication
It calculates and after saturation arithmetic processing, obtains input gain adjustment signal；
Selecting unit, including：It is mode signal input terminal, defeated for receiving the first choice signal of the digital output signal
Enter end, adjust the second selection signal input terminal and selection signal output end of signal for receiving the input gain；It is described
The mode signal that selection signal output end is used to be received according to the mode signal input terminal, selectivity export the numeral output
Signal or the input gain adjust signal；
Automatic gain control unit generates the automatic increasing for the output signal according to the selection signal output end
Beneficial stairstep signal.
Preferably, double AGC systems further include：
Prevent big unit, for according to preset amplifying parameters, being amplified processing to the digital input signals, obtaining
The digital input signals of amplification；
The output gain adjustment unit includes the first multiplier and the first saturation arithmetic processor, first multiplier
The digital input signals of the amplification and the first product of the first gain adjustment value are calculated, the first saturation arithmetic processor is used
In carrying out saturation arithmetic processing to first product, the digital output signal is obtained；
The input gain adjustment unit includes the second multiplier and the second saturation arithmetic processor, second multiplier
The digital input signals of the amplification and the second product of the second gain adjustment value are calculated, the second saturation arithmetic processor is used
In carrying out saturation arithmetic processing to second product, the input gain adjustment signal is obtained.
Preferably, double AGC systems further include absolute value calculation unit, the input terminal of the absolute value calculation unit
Connect the selection signal output end of the selecting unit；The output end of the absolute value calculation unit connects the automatic gain control
The input terminal of unit processed；
The automatic gain control unit is used for the output signal of the output end according to the absolute value calculation unit, raw
At the automatic gain stairstep signal.
Table 1 lists the meaning to each symbology in Fig. 3, and table 2 lists the meaning to each symbology in Fig. 4.Fig. 4
Control signal in bracket is all configurable parameter, is suitable for various occasions to the very big flexibility of the present invention.Automatically
Gain control unit is exactly mainly to be judged into line amplitude input signal abs_agc, obtains the gain stepping acc_ for needing to adjust
cnt[5:0]。
Table 1
Table 2
The present embodiment is again carried out the gain of input signal after signal zero passage detection by the anticipation of digital input signal
Adjustment, signal overvoltage can be effectively prevent, which to contract, leads to the too early change of voice of audio signal.Meanwhile pretreatment of the present invention for signal
Also there is improvement, in the digital quantization signal Din [15 of 16bits:0] after, the present invention carries out pre-amplification to this signal, can be effective
Improve the dynamic range of digital signal.For the present invention on the judgement source to automatic gain, also having can be by configuring selection warp
Cross the input quantized signal after the later output quantization signals of AGC either pre-amplification.In this way on the application scenarios of AGC,
There is more flexible selection.The present embodiment carries out dynamic realtime adjustment to the amplitude of audio signal, retain to greatest extent primary sound and
Reduce the risk of signal truncation and signal overcompression.
As shown in fig. 6, specifically, the automatic gain control unit includes：
Reset signal end, fast gain Enable Pin and slow gain Enable Pin；
Signal peak monitoring modular, for judging whether the input signal of the automatic gain control unit is more than preset
Quick AGC amplitude thresholds, at a slow speed AGC amplitude thresholds and AGC as shown in Figure 5 discharges amplitude threshold, is given birth to according to judging result
At corresponding monitor value, the monitor value includes quick AGC amplitudes monitor value, at a slow speed AGC amplitudes monitor value and AGC release width
Spend monitor value；
Major state machine (FSM_Controller), for being counted according to preset fast gain count value, slow gain
Device, the correspondence for keeping gain count value and various monitor values and the working condition of each automatic gain control unit determine
Working condition in the corresponding monitor value, and export current work state information and subsequent work status information；Institute
State the following various states that working condition includes as shown in Figure 7：Release to the digital input signals without Gain tuning
State, digital input signal carry out the tracking mode of faster slower speed Gain tuning, maintain digital input signals in fixed gain width
The hold mode of output under degree；
Fast gain counter, for according to the current work state information and subsequent work status information and in advance
If quick AGC adjust a step gain need duration, counted, obtain the fast gain count value；
Slow gain counter, for according to the current work state information and subsequent work status information and in advance
If AGC at a slow speed adjust a step gain need duration, counted, obtain the slow gain count value；
Gain counter is kept, for according to the current work state information and subsequent work status information and in advance
If holding AGC amplitudes when adjust a step gain needs duration, counted, obtain the holding gain count value；
Gain step by step modulating module, for according to the current work state information, subsequent work status information, quickly
Gain count value, slow gain counter, quick AGC amplitudes monitor value, at a slow speed AGC amplitudes monitor value and AGC discharge amplitude
Monitor value generates the automatic gain stairstep signal, and the automatic gain stairstep signal amplitude limit is in preset gain step by step modulating
Maximum value.
As shown in figure 8, the zero passage detection unit, including：
First delay time register, first end is for receiving the digital input signals, second end for receiving clock signal
And first output end；
Logic or non-operation module, first end is for receiving the digital input signals, second end for receiving described the
The signal and second output terminal of the output end of one delay time register；
Logic or computing module, first end are used to receive digital input signals detection knot minimum near positive value
Fruit, second end are for receiving digital input signals testing result minimum near negative value and third end for receiving
The output signal of the second output terminal, and the third output end for exporting zero passage detection signal.
It crosses zero adjustment and ensure that signal only carries out Gain tuning when zero crossing to signal amplitude, avoid too early tune
Entire signal gain leads to the sound change of voice or has the appearance of pop sounds, makes the adjustment of sound more smooth soft.Pay attention to：Cross zero adjustment
Detection all just in the Din [15 of input:0] signal.Because only that adjust gain when to the zero passage of input signal, is only
The target of AGC.
Further, the gain linearization unit includes：
Adder, for be calculated gain that pre-set yield value is added with automatic gain stairstep signal and
Value；
Second delay time register, including：Data input pin for receiving the gain and value, clock signal input terminal end,
Enable Pin for receiving the zero passage detection signal and delayed data output end；
Selector, including：Enable Pin for receiving the zero passage detection signal, for receiving the gain and value
One selection input terminal, the second selection input terminal for connecting the delayed data output end, and selection output end, the choosing
Output end is selected for according to the zero passage detection signal, the gain and value or delayed data output to be received in selectivity output
The output signal at end；
First table look-up module, for finding linearisation in linear look-up table according to the output signal of the selection output end
The first gain adjustment value；
Second table look-up module, the second gain tune for finding linearisation in linear look-up table according to the gain and value
Section value.
Fig. 8 Gain Linear Table therein are exactly the look-up table linearized：Linearisation is found by step gain
Gain, feed back to input, output gain adjustment module.And the adjustment of gain be exactly input signal, output feedback signal it is direct
Be multiplied with linear gain (multiplier) and by saturation arithmetic (Saturation) and complete.
With continued reference to Fig. 8, the gain linearization unit further includes：The input terminal of clipping module, the clipping module connects
The output end of the adder is connect, the output end of the clipping module connects the data input pin of second delay time register.
Table 3 is the meaning of each symbol in Fig. 8.
Table 3
Continue as shown in fig. 7, the entry condition of the release conditions includes：
The reset signal end receives reset signal, and the fast gain Enable Pin and slow gain Enable Pin are not received
To enable signal；Alternatively,
In hold mode, the signal peak monitoring modular can't detect the input letter of the automatic gain control unit
Number beyond the quick AGC amplitude thresholds, AGC amplitude thresholds and AGC discharge amplitude threshold at a slow speed, are keeping gain counter
Enter the release conditions after meter is full；
The condition that the release conditions enter tracking mode includes：The signal peak monitoring modular detects described automatic
The input signal of gain control unit AGC amplitude thresholds beyond the quick AGC amplitude thresholds or at a slow speed.
Following intuitive way can also be used to describe release conditions above：
1. release conditions【Release】
Process content
It can be at this time to signal without Gain tuning, in dynamic range of signals
Come from preceding state
Reset signal rst_n is effective.(rst_n=0)
The module of the present invention is not enabled.(enable=0)
【It keeps】1) in hold mode, the threshold value beyond Fast/Slow is can't detect,
And it is also not above release threshold value, release conditions are entered after holding _ cnt counters are write all over.
It is transferred to next state
【Tracking】1) amplitude threshold (above_avth1=1) more than quick AGC is detected
2) amplitude threshold (above_avth0=1) more than AGC at a slow speed is detected
It is maintained at this state
Other conditions
Further, the entry condition of the tracking mode includes：
The signal peak monitoring modular detects the input signal of the automatic gain control unit beyond described quick
AGC amplitude thresholds or at a slow speed AGC amplitude thresholds；
The condition that the tracking mode enters hold mode includes：
The input signal that the signal peak monitoring modular detects the automatic gain control unit is quick without departing from described
AGC amplitude thresholds and at a slow speed AGC amplitude thresholds.
Following intuitive way can also be used to describe tracking mode above：
2. AGC tracking modes【Tracking】
Process content
Quick, slow gain adjustment is carried out to signal, ensures signal not truncation, and keep high-power output
Come from preceding state
【IDLE】1) amplitude threshold (above_avth1=1) more than quick AGC is detected
2) amplitude threshold (above_avth0=1) more than AGC at a slow speed is detected
【It keeps】1) amplitude threshold (above_avth1=1) more than quick AGC is detected
2) amplitude threshold (above_avth0=1) more than AGC at a slow speed is detected
It is transferred to next state
【It keeps】1) signal threshold value is detected, the threshold value of quick AGC and at a slow speed AGC are not
More than (above_avth1=0 and above_avth0=0)
It is maintained at this state
Other conditions
Further, the entry condition of hold mode includes：
In the tracking mode, the signal peak monitoring modular detects the input letter of the automatic gain control unit
Number without departing from the quick AGC amplitude thresholds and at a slow speed AGC amplitude thresholds；
In the hold mode, the signal peak monitoring modular detects the input letter of the automatic gain control unit
Number beyond AGC discharge amplitude monitor value；
The hold mode enter the tracking mode condition include：
The signal peak monitoring modular can't detect the input signal of the automatic gain control unit beyond described fast
Fast AGC amplitude thresholds, at a slow speed AGC amplitude thresholds and AGC discharge amplitude threshold, and the holding gain counter counts are full.
Following intuitive way can also be used to describe hold mode above：
3. hold mode【It keeps】
Process content
Signal does not need adjust gain at this time, maintains output of the signal under fixed gain amplitude.
Come from preceding state
【Tracking】1) it can't detect the amplitude threshold (above_avth1 more than quick AGC
=0) and it can't detect amplitude threshold (above_avth0=0) more than AGC at a slow speed
【It keeps】1) the release amplitude threshold (above_rvth=1) more than AGC is detected
It is transferred to next state
【Release】1) release counter counts expire (holding _ cnt>=holding _ time_th), and do not detect more than AGC
It is quick, at a slow speed, release amplitude threshold.(above_avth1=0 and above_avth0=0 and above_rvth=0)
It is maintained at this state
Other
Fig. 9 is a simple declaration of the saturation arithmetic of the tape symbol signal of the present invention, by SSAT (Signed
Saturation signal) exports as the digital audio and video signals normally after Gain tuning.It can be seen from the figure that：If
Without saturation arithmetic, signal has distortion.And saturation arithmetic is can to ensure that signal does not distort.
In conjunction with above each figure, the operation principle of double AGC systems is summarized as follows：Audio quantization signal Din [15:0] it is passing through
It after crossing pre-amplification, adjusts by output gain signal, and is exported after saturation arithmetic is handled.Input signal passes through zero passage detection
Afterwards, then the adjust gain linearization process generated to automatic gain control unit respectively adjusts the signal for inputting, exporting and increases
Benefit, the signal after adjustment are transmitted back to automatic gain control unit by the way that the configuration in source may be selected, further adjust signal again
Gain stepping.
In the detailed design block diagram present invention of the present invention, the digital signal of quantization passes through pre-amplification, in automatic growth control
The AGC gain stepping that module calculates, when signal zero passage, by searching for the corresponding linear gain of gain stepping, by it with
Signal after pre-amplification does multiplication and saturation arithmetic, obtains final output gain.Present invention uses export and input two kinds
Feedback adjusts function to detect gain by built-in quick, slow gain, and gain-adjusted is carried out to signal.It ensure that
Signal can quick adjust gain not truncation, and can ensure high-power stabilization set output signal under slow gain conciliation.Due to existing
In the pursuit for sound quality, music sense of hearing, double AGC frameworks circuits of the invention have good more scene applicabilities.This frame
The circuit of structure can：1, the dynamic range certain to signal boost, realization method is very simple, can be easily achieved, also may be used
Retain original signal by configurable with odd jobs.2, due to dual signal source may be selected, height gain compression threshold value is optional, can match
It sets, Signal Compression ratio and compression ratio dynamic can match and good universal characteristic, double AGC frameworks of the invention can be widely applied to
In digital audio-power amplifier chip and the chip of the similar relevant Digital Signal Processing of needs.
It will appreciated by the skilled person that realizing all or part of step/units/modules of above-described embodiment
It can be completed by the relevant hardware of program instruction, foregoing routine can be stored in computer read/write memory medium, should
When being executed, it includes the step corresponded in above-described embodiment each unit to execute to program；And storage medium above-mentioned includes：ROM,
The various media that can store program code such as RAM, magnetic disc or optical disc.
Particular embodiments described above has carried out further in detail the purpose of the present invention, technical solution and advantageous effect
It describes in detail bright, it should be understood that the above is only a specific embodiment of the present invention, is not intended to restrict the invention, it is all
Within the spirit and principles in the present invention, any modification, equivalent substitution, improvement and etc. done should be included in the guarantor of the present invention
Within the scope of shield.
Claims (10)
1. a kind of double AGC systems, which is characterized in that including：
Zero passage detection unit, for detect digital input signals whether zero passage；
Gain linearization unit, in the digital input signals zero passage, linearly being looked into according to automatic gain stairstep signal
It looks in table and finds the first gain adjustment value and the second gain adjustment value of linearisation；
Output gain adjustment unit, for according to the digital input signals and the first gain adjustment value, by multiplying and
After saturation arithmetic processing, digital output signal is obtained；
Input gain adjustment unit, for according to the digital input signals and the second gain adjustment value, by multiplying and
After saturation arithmetic processing, input gain adjustment signal is obtained；
Selecting unit, including：Mode signal input terminal is inputted for receiving the first choice signal of the digital output signal
End, the second selection signal input terminal and selection signal output end that signal is adjusted for receiving the input gain；The choosing
Mode signal of the signal output end for being received according to the mode signal input terminal is selected, selectivity exports the numeral output letter
Number or the input gain adjust signal；
Automatic gain control unit generates the automatic gain step for the output signal according to the selection signal output end
Inlet signal.
2. double AGC systems as described in claim 1, which is characterized in that further include：
Prevent big unit, for according to preset amplifying parameters, being amplified processing to the digital input signals, being amplified
Digital input signals；
The output gain adjustment unit includes the first multiplier and the first saturation arithmetic processor, and first multiplier calculates
First product of the digital input signals of the amplification and the first gain adjustment value, the first saturation arithmetic processor for pair
First product carries out saturation arithmetic processing, obtains the digital output signal；
The input gain adjustment unit includes the second multiplier and the second saturation arithmetic processor, and second multiplier calculates
Second product of the digital input signals of the amplification and the second gain adjustment value, the second saturation arithmetic processor for pair
Second product carries out saturation arithmetic processing, obtains the input gain adjustment signal.
3. double AGC systems as claimed in claim 2, which is characterized in that further include absolute value calculation unit, the absolute value meter
The input terminal for calculating unit connects the selection signal output end of the selecting unit；The output end of the absolute value calculation unit connects
The input terminal of the automatic gain control unit；
The automatic gain control unit is used for the output signal of the output end according to the absolute value calculation unit, generates institute
State automatic gain stairstep signal.
4. double AGC systems as claimed in any one of claims 1-3, which is characterized in that the automatic gain control unit packet
It includes：
Reset signal end, fast gain Enable Pin and slow gain Enable Pin；
Signal peak monitoring modular, for judging whether the input signal of the automatic gain control unit is more than preset quick
AGC amplitude thresholds, at a slow speed AGC amplitude thresholds and AGC discharge amplitude threshold, and corresponding monitor value is generated according to judging result,
The monitor value includes quick AGC amplitudes monitor value, at a slow speed AGC amplitudes monitor value and AGC release amplitude monitor values；
Major state machine, for according to preset fast gain count value, slow gain counter, keep gain count value and
The correspondence of various monitor values and the working condition of each automatic gain control unit is determined in the corresponding monitor value
Working condition, and export current work state information and subsequent work status information；The working condition includes：To the number
Word input signal carries out the tracking shape of faster slower speed Gain tuning without release conditions, the digital input signal of Gain tuning
State, the hold mode for maintaining output of the digital input signals under fixed gain amplitude；
Fast gain counter, for according to the current work state information and subsequent work status information and preset
Quick AGC adjusts the duration that a step gain needs, and is counted, obtains the fast gain count value；
Slow gain counter, for according to the current work state information and subsequent work status information and preset
AGC adjusts the duration that a step gain needs at a slow speed, is counted, obtains the slow gain count value；
Gain counter is kept, for according to the current work state information and subsequent work status information and preset
It the duration for keeping adjusting a step gain needs when AGC amplitudes, is counted, obtains the holding gain count value；
Gain step by step modulating module, for according to the current work state information, subsequent work status information, fast gain
Count value, slow gain counter, quick AGC amplitudes monitor value, at a slow speed AGC amplitudes monitor value and AGC release amplitude monitorings
Value, generates the automatic gain stairstep signal, the automatic gain stairstep signal amplitude limit in preset gain step by step modulating most
Big value.
5. double AGC systems as claimed in claim 4, which is characterized in that the zero passage detection unit, including：
First delay time register, first end for receive the digital input signals, second end for receive clock signal and
First output end；
Logic or non-operation module, first end is for receiving the digital input signals, second end is used to receive described first and prolong
Delay in the dispatch of storage output end signal and second output terminal；
Logic or computing module, first end are used to receive the digital input signals in the positive value nearby testing result of minimum, the
Two ends are for receiving digital input signals testing result minimum near negative value and third end for receiving described the
The output signal of two output ends, and the third output end for exporting zero passage detection signal.
6. AGC systems as claimed in claim 5 double, which is characterized in that the gain linearization unit includes：
Adder, for the gain and value that pre-set yield value is added with automatic gain stairstep signal to be calculated；
Second delay time register, including：For receiving the gain and value, clock signal input terminal end is used for data input pin
Receive the Enable Pin and delayed data output end of the zero passage detection signal；
Selector, including：Enable Pin for receiving the zero passage detection signal, the first choosing for receiving the gain and value
Input terminal is selected, the second selection input terminal for connecting the delayed data output end, and selection output end, the selection are defeated
Outlet is used for according to the zero passage detection signal, and the gain and value or the delayed data output end are received in selectivity output
Output signal；
First table look-up module, for finding the of linearisation in linear look-up table according to the output signal of the selection output end
One gain adjustment value；
Second table look-up module, the second gain-adjusted for finding linearisation in linear look-up table according to the gain and value
Value.
7. double AGC systems as described in claim 6, which is characterized in that the gain linearization unit further includes：Amplitude limit mould
Block, the input terminal of the clipping module connect the output end of the adder, the output end connection of the clipping module described the
The data input pin of two delay time registers.
8. AGC systems as claimed in claim 4 double, which is characterized in that the entry condition of the release conditions includes：
The reset signal end receives reset signal, and the fast gain Enable Pin and slow gain Enable Pin, which do not receive, to be made
It can signal；Alternatively,
In hold mode, the input signal that the signal peak monitoring modular can't detect the automatic gain control unit is super
Go out the quick AGC amplitude thresholds, at a slow speed AGC amplitude thresholds and AGC release amplitude thresholds, keeps gain counter counts full
Enter the release conditions afterwards；
The condition that the release conditions enter tracking mode includes：The signal peak monitoring modular detects the automatic gain
The input signal of control unit AGC amplitude thresholds beyond the quick AGC amplitude thresholds or at a slow speed.
9. AGC systems as claimed in claim 4 double, which is characterized in that the entry condition of the tracking mode includes：
The signal peak monitoring modular detects that the input signal of the automatic gain control unit exceeds the quick AGC width
Spend threshold value or at a slow speed AGC amplitude thresholds；
The condition that the tracking mode enters hold mode includes：
The signal peak monitoring modular detects the input signal of the automatic gain control unit without departing from the quick AGC width
Spend threshold value and at a slow speed AGC amplitude thresholds.
10. AGC systems as claimed in claim 4 double, which is characterized in that the entry condition of hold mode includes：
In the tracking mode, the signal peak monitoring modular detects the input signal of the automatic gain control unit not
Beyond the quick AGC amplitude thresholds and at a slow speed AGC amplitude thresholds；
In the hold mode, the input signal that the signal peak monitoring modular detects the automatic gain control unit is super
Go out AGC release amplitude monitor values；
The hold mode enter the tracking mode condition include：
The input signal that the signal peak monitoring modular can't detect the automatic gain control unit exceeds the quick AGC
Amplitude threshold, at a slow speed AGC amplitude thresholds and AGC discharge amplitude threshold, and the holding gain counter counts are full.
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| CN111478675A (en) * | 2020-04-14 | 2020-07-31 | 上海艾为电子技术股份有限公司 | Audio signal processing system, audio signal processing method and electronic equipment |
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