CN1020516C - Processing circuit for signal - Google Patents

Abstract

The present invention is a signal processing electric circuit, which can detect the signal information of the simulation regenerated signal read out by the recording medium and transform the signal information into impulse signal. Wherein, an AGC control signal is used for sampling the title part signal amplitude of the simulation regenerated signal read out by the recording medium, and the sample is controlled at a constant value by the AGC amplifier used. The AGC control circuit is used to judge whether the above title part signal amplitude is normal or not. During the abnormal state, an instruction is sent out to make the AGC amplifier not to work, and the data increasing part signal amplitude not amplified abnormally, therefore, the detection mistake is prevented and the reliability of the data regeneration is enhanced.

Description

Processing circuit for signal

The present invention relates to a kind of optical recorder that uses signal processing circuit, in this signal processing circuit,, make the control of AGC(automatic gain when the regenerated signal amplitude occurs when unusual) amplifier quits work.

Fig. 4 to Fig. 8 is the accompanying drawing that shows prior art.Fig. 4 illustrate recording medium from interior road to the outer course heading part and the amplitude of adding the data division regenerated signal, Fig. 5 is a sector record form pie graph common in the past when record adds data on recording medium, Fig. 6 a and Fig. 6 b illustrate the example figure of regenerated signal waveform on the interior road of optical recording media and the outer course, Fig. 7 is that Fig. 8 illustrates the oscillogram of each several part signal among Fig. 7 at number the 224th page of signal processing circuit skeleton diagram in the past of going up publication " Nikkei electron " in February, 1987.

In the sector record form shown in Figure 5, the 11st, each sector is obtained synchronously and the sector label that is provided with, the 12nd, the address that the track address and the sevtor address of recording medium (not shown) are made record, the 13rd, whether this sector is write down the mark of making record fully, the 14th, for the automatic phase control circuit (not shown) realizes the boot that frequency pulling and phase pulling are provided with at short notice, so that automatic phase control circuit takes out the clock composition from recorded data.Generally, these boot 14 records is the interior highest frequencies of data 15 medium frequency compositions.

Sector label 11 and address 12 are recorded on the recording medium in advance, and they are called title division (A).And mark 13, boot 14 and data 15 are not recorded on the recording medium in advance, and by record after the record regenerator (not shown), they are called adds data division (B).

Fig. 6 a illustrates recording medium interior road heading part (A) and adds the regenerated signal of data division (B), and Fig. 6 b illustrates recording medium outer course heading part (A) and adds the regenerated signal of data division (B).

Fig. 4 illustrate recording medium from interior road the regenerated signal amplitude to outer course heading part (A) and interpolation data division (B).

Fig. 7 represents signal processing circuit in the past, the 1st, wave filter, noise in the simulation regenerated signal that provides in order to filtering recording medium beyond the useful band, the 4th, the amplitude of the regenerated signal of wave filter 1 output is amplified to the AGC amplifier of certain value, the 5th, the output signal of AGC amplifier 4 is carried out the differentiating circuit of differential, the 6th, detect the title testing circuit of information title division in the output signal of differentiating circuit 5 (A) regenerated signal, the 7th, in the output signal of differentiating circuit 5, add the interpolation data detection circuit of the information that detects data division (B) regenerated signal, the 8th, pulse-generating circuit produces and adds the corresponding pulse of data detection circuit 7 detected information.

In above-mentioned such signal processing circuit in the past that constitutes, the regenerated signal that recording medium provides at first is input to wave filter 1, there the noise frequency composition outside the filtering useful band.The output signal of wave filter 1 (1a) is fed to back grade AGC amplifier 4, regenerated signal is amplified.It is a steady state value that automatic gain control makes the regenerated signal peak-to-peak amplitude of title division.For sector record form pie graph shown in Figure 5, as going up about shown in the regenerated signal oscillogram of title division (A) in the recording medium outer course and interpolation data division (B) about title division in the road in the recording medium (A) and the regenerated signal oscillogram and Fig. 6 b that add data division (B) on Fig. 6 a, the regenerated signal changes in amplitude that causes because of the regenerative track address of recording medium, and the regenerated signal changes in amplitude that causes because of other reason, agc circuit all can be suppressed, and making amplitude is a steady state value.

See Fig. 7 again, the output signal of AGC amplifier 4 (4a) is carried out differential by the differentiating circuit 5 of back level, and the waveform of its output signal (5a) as shown in Figure 8.This output signal (5a) is fed on title testing circuit 6 and the interpolation data detection circuit 7 in parallel with it.On the one hand, from contrasting, the output signal (6a) of the output signal (5a) of Fig. 8 codifferential circuit 5 and title testing circuit 6 can learn, owing to have the first comparative level X and the second comparative level Y, rising, negative edge position at the regenerated signal waveform of title division (A), when the output signal (5a) that is produced by differentiating circuit 5 alternately surpassed the first comparative level X and the second comparative level Y, title testing circuit 6 was because of being subjected to triggering, overturning and produce output signal (6a) successively; Just, this output signal (6a) is the square wave digital signal, it include in the regenerated signal waveform of title division (A) rise, the information of negative edge.On the other hand, from contrasting, the output signal (5a) of Fig. 8 codifferential circuit 5 and the output signal (7a) of adding data detection circuit 7 can know, owing to have comparative level Z, when the output signal (5a) of differentiating circuit 5 surpasses comparative level Z, add data detection circuit 7 and produce output signal (7a) because of monostable effect; Just, output signal (7a) is a digital signal, and it includes the peak point information of the regenerated signal waveform that adds data division (B).

The output signal (7a) of adding data detection circuit 7 is fed on the pulse-generating circuit 8 of back level, removes by the pulse that comprises in the output signal (7a), may be formed by noise (adding the pulse shown in the middle dotted line of output signal (7a) of data detection circuit 7 among Fig. 8).

In the signal processing circuit in the past, when as the title division regenerated signal of automatic gain controlling object because recording medium defectives etc. are former thereby during the amplitude of generation abnormal conditions, this is not provided with safeguard measure.So, because of the effect of AGC amplifier makes follow-up interpolation data division that unusual amplification also take place, cause its regenerated signal amplitude excessive or too small, so can not set the optimum level that detection signal is used.Therefore, exist the bad problem of signal detection performance that detects mistake etc.

The objective of the invention is in order to obtain a kind of signal processing circuit that addresses the above problem, when the amplitude of title division regenerated signal arrives outside the regulation permissible range unusually, the effect that can not occur because of the AGC amplifier makes the unusual phenomenon of amplifying of regenerated signal, so thereby can overcome the problem of signal detection performance difference.

Be provided with two circuit in the signal processing circuit that the present invention relates to, one is the AGC amplifier of ride gain, it makes the title division signal amplitude of the simulation regenerated signal of reading from recording medium remain in a steady state value, another is the AGC control circuit, it judges that the title division signal amplitude whether within setting, produces the send as an envoy to work of above-mentioned AGC amplifier or idle signal thus.

Among the present invention, when just thinking that title division regenerated signal amplitude as the AGC object is in setting, the AGC amplifier just plays the automatic gain control action, and when (because recording medium is unusual), it does not play the automatic gain control action beyond setting.Because gain is fixed on the suitable certain value (for example gain=1), even when title division regenerated signal amplitude is unusual, the unusual situation of amplifying of AGC amplifier can not take place yet, therefore, add the input of data division and can normally carry out.

Fig. 1 is the block scheme of one embodiment of the present of invention;

Fig. 2 is the timing diagram of AGC control signal and damping capacity setting value;

Fig. 3 is the oscillogram of each several part regenerated signal among Fig. 1;

Fig. 4 illustrate recording medium from interior road to the outer course heading part and the amplitude of adding the data division regenerated signal;

Fig. 5 is a sector record form pie graph in the past;

Fig. 6 a and Fig. 6 b are the oscillogram examples of regenerated signal on road and the outer course in the past the optical recording media;

Fig. 7 is a signal processing circuit block scheme in the past;

Fig. 8 is the oscillogram of each several part regenerated signal among Fig. 7.

Among Fig. 1,4A is the AGC amplifier, the 9th, and the AGC control circuit.

In addition, the same-sign among each figure is represented identical or suitable part.

Fig. 1 is the block scheme of one embodiment of the present of invention, wherein, 1 and 5～more than 8 parts be with the prior art circuit in identical.Among Fig. 1, the noise in the simulation regenerated signal that wave filter 1 filtering recording medium provides; The 2nd, prime amplifier, the amplitude of the output signal (1a) of adjustment wave filter 1; The 3rd, attenuator is set damping capacity to title division (A) in the output signal (2a) of prime amplifier 2 and interpolation data division (B); 4A is the AGC amplifier that the signal amplitude of title division (A) in the output signal of attenuator 3 (3a) is placed certain value; The 9th, the AGC control circuit, when just thinking that regenerated signal amplitude as the title division (A) of automatic gain control reference signal is in specialized range, it just makes AGC amplifier 4A work.

Below, the working condition of signal processing circuit of the present invention is described.From the regenerated signal feed-in wave filter 1 of recording medium, the noise frequency composition outside the filtering useful band.The output signal of wave filter 1 (1a) is fed to the prime amplifier 2 of back level, and signal amplitude is adjusted in the specialized range.The output signal of prime amplifier 2 (2a) is fed to the attenuator 3 of back level.For attenuator 3, carry out the determined optimum value of input according to the ratio of the regenerated signal amplitude of title division (A) and the regenerated signal amplitude of adding data division (B), preestablished damping capacity setting value (3b); That is, as shown in Figure 2, damping capacity setting value (3b) for example is set at Ah(dB at title division (A)), be set at Ad(dB at interpolation data division (B)), therefore, the ratio of title division (A) with the signal amplitude of adding data division (B) can be set on the setting.Usually, shown in Fig. 6 a and Fig. 6 b, the recording density of title division (A) is more sparse, thus waveform be not subject to disturb, its signal amplitude as shown in Figure 4, it has steady state value to outer course from the interior road of recording medium.On the other hand, amplitude is little because recording density is close and waveform is disturbed in interior road side for the signal amplitude of the highest frequency component of interpolation data division (B), therefrom to the outer course side steady state value is arranged then near the road.Therefore, the damping capacity setting value (3b) of the attenuator 3 shown in Fig. 2 is with regard to the damping capacity Ah(dB of title division (A)) with the damping capacity Ad(dB that adds data division (B)) beguine set according to track address, making it for input is optimum value.

Key diagram 1 back.The output signal of attenuator 3 (3a) is fed to the AGC amplifier 4A of back level.By AGC control signal (4b) signal amplitude of title division (A) is taken a sample, so as to the magnification of automatic setting AGC amplifier 4A, making the signal waveform peak-to-peak amplitude is a steady state value.As shown in Figure 2, the gain control of AGC amplifier 4A is only located to carry out at title division (A), locates not carry out controlling at interpolation data division (B).In order to keep the gain of front title division (A), AGC control signal (4b) is input to AGC amplifier 4A.AGC control signal (4b) for example is one and locates to locate signal into high level for low level, adding data division (B) at title division (A).In addition, as shown in fig. 1, the output signal of attenuator 3 (3a) also is fed to AGC control circuit 9, whether the regenerated signal amplitude of judging title division (A) there is within the permissible range of regulation, AGC amplifier 4A just works in the time of only in the permissible range of regulation, and it is not worked in the time of beyond the permissible range of regulation.(gain for example is set at 1 when AGC does not work.) output signal (9a) the control AGC amplifier 4A that provided by AGC control circuit 9 plays or do not rise the automatic gain control action.The differentiating circuit 5 that the output signal (4aA) of AGC amplifier 4A is fed to the back level carries out differential.The output signal of differentiating circuit 5 (5aA) is fed to the title testing circuit 6 of back level, detects the rising that waveform is arranged, negative edge as the information of title division (A) there.In addition, the output signal of differentiating circuit 5 (5aA) also is fed to adds data detection circuit 7, detects the waveform peak as the information of adding data division (B) there.The output signal (7aA) of adding data detection circuit 7 is fed to the pulse-generating circuit 8 of back level, removes the pulse that comprises in output signal (7aA), may be formed by noise.

Fig. 3 has illustrated above-mentioned title division (A) and has added the signal detection process of data division (B), regenerated signal as the title division (A) of the input signal (4aA) of differentiating circuit 5, carry out differential by differentiating circuit 5, at rising, falling edge, produce the pulse type output signal (5aA) of positive and negative corresponding to the waveform of the information of input signal (4aA).This signal (5aA) compares with the first comparative level X and the second comparative level Y of the title testing circuit 6 of back level, the output signal of title testing circuit 6 (6aA) is such as shown, is that the regenerated signal waveform that includes title division (A) rises, the digital output signal (6aA) of negative edge information.In addition, the regenerated signal as the interpolation data division (B) of the input signal (4aA) of differentiating circuit 5 carries out differential by differentiating circuit 5, and its output signal (5aA) has waveform as shown in the figure.It compares with the comparative level Z of the interpolation data detection circuit 7 of back level, provides the digital output signal (7aA) that includes the regenerated signal waveform peak dot information that adds data division (B).

Now, in order to help to understand the present invention, the present invention compared with in the past circuit be illustrated.For example, suppose from the title division regenerated signal amplitude of recording medium and make it more much smaller than the signal amplitude of adding data division owing to the defective of recording medium etc.

When being input to this regenerated signal in the signal processing circuit in the past shown in Figure 7, because the signal amplitude of title division (A) is very little in the input signal (1a) of AGC amplifier 4, it is very big that the gain of AGC amplifier 4 becomes, so the regenerated signal amplitude of interpolation data division (B) is very big in the output signal of AGC amplifier 4 (4a).Therefore, as shown in Figure 8, noise level will reach the comparative level Z that adds data detection circuit 7, and the result can come out the walkaway shown in the dotted line.

In contrast, when regenerated signal is input in the signal processing circuit of the present invention, because the amplitude of title division (A) is very little in the input signal (3a) of AGC amplifier 4A, be judged to be by AGC control circuit 9 and be in beyond the specialized range, so AGC control circuit 9 does not make AGC amplifier 4A work, its gain is suppressed on the little value (for example 1).Therefore, as shown in Figure 3, the amplitude of adding data division (B) in the output signal (4aA) of AGC amplifier 4A can be not excessive, and noise level does not reach the comparative level Z that adds data detection circuit 7, thereby noise is unlikely is detected, and the reliability of detection is improved.

As top detailed description, when as the title division regenerated signal amplitude of AGC controlling object when unusual, the present invention is owing to have the AGC control circuit, can send the instruction that does not make the work of AGC amplifier, so even title division regenerated signal amplitude takes place unusually, amplify singularly owing to suppressed the regenerated signal amplitude of interpolation data division, thereby can prevent to add data detection circuit appearance detection mistake, can obtain the high data reproduction effect of reliability.

Claims (1)

1, a kind of optical recorder that wherein uses signal processing circuit, described signal processing circuit detects the information of the simulation regenerated signal of reading from recording medium, and be converted into pulse signal, it is characterized in that described signal processing circuit comprises: the AGC amplifier, by the AGC control signal amplitude of title part signal in the above-mentioned regenerated signal is taken a sample, its amplitude is controlled on the steady state value with described AGC amplifier; The AGC control circuit is by judging that whether above-mentioned title division signal amplitude judges whether above-mentioned title division signal amplitude is unusual, and send instruction when amplitude is unusual in the range value of regulation, do not work described AGC amplifier.

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