CN1296908C - Sawtooth wave bit value detecting circuit - Google Patents

Abstract

The present invention relates to a sawtooth wave bit value detecting circuit which is used for detecting a bit value of a sawtooth wave of a wave signal with the fundamental frequency of f<wob>. The detecting circuit comprises a first band-pass filter, a second band-pass filter, a first comparator, a second comparator, a delay unit and a sampling unit, wherein the first band-pass filter filters the wave signal by the central frequency of 2*f<wob>, and generates a first filtering signal; the second band-pass filter filters the wave signal by the central frequency of f<wob>, and generates a second filtering signal; the first filtering signal is compared with reference voltage by the first comparator, and the first comparator generates a double frequency signal; the second filtering signal is compared with the reference voltage by the second comparator, and the second comparator generates a fundamental frequency signal; the delay unit receives the fundamental frequency signal, and outputs a delay signal after delayed for preset delay time; the sampling unit samples the double frequency signal when the delay signal is used as a sampling time pulse, and outputs a sampling value to be used as the bit value of the sawtooth wave.

Description

Sawtooth wave bit value testing circuit

Technical field

The invention relates to sawtooth wave bit value testing circuit.

Background technology

Because the progress of optical disc, the erasable form of CD (Disc Rewritable Format) that is defined as a new generation of Blue-Ray is just like given birth to.The wave of the track of the erasable form of this Blue-Ray CD is from the more or less sine skew (sinusoidal deviation) of average centerline (average centerlines).(nominal wobble length NWL) is equivalent to 69 channel bits (channel bits) to a kind of small wave length.For the repeated writing optical disk (Rewritable disc) of user's data quantity (user data capacity) that each layer has 23.3GB, small wave length is necessary for 5.5200 μ m ± 0.005 μ m; For the repeated writing optical disk of user's data quantity that each layer has 25.0GB, small wave length is necessary for 5.1405 μ m ± 0.005 μ m; And for the repeated writing optical disk of user's data quantity that each layer has 27.0GB, small wave length is necessary for 4.7610 μ m ± 0.005 μ m.And, be corresponding to basic frequency f _WobOn the reference velocity of=956.522kHz (Reference Velocity).

The basic configuration of wave is cosine wave (CW) (cosine): cos{2 π * f _Wob* t}.Wave with this basic configuration be called as dull wave (Monotone wobble, MW).There are some waves wherein to be had two kinds of modulating methods to be used simultaneously by modulation.First kind of minimum key value of moving (Minimum Shift Keying-cosine variant is hereinafter to be referred as MSK-cos) that modulating method is a varies with cosine, and second method is harmonic modulation ripple (Harmonic Modulated Wave is hereinafter to be referred as HMW).3 zones of the zone of protection of (outer zone) (protection zone) in the outer ring, rill (groove) only utilizes the MSK-cos modulation, rather than HMW.And (Address In Pre-groove is to be represented by two kinds of modulating methods ADIP) in the rill address.

Fig. 1 shows the definition of MSK mark.The method of MSK-cos modulation is that (MSK mark MM) replaces three dull wave MW with a MSK mark each time.As shown in the drawing, a MSK mark comprises three small wave length N WL, and is defined as follows: first NWL is frequency 1.5*f _WobSine wave (cos{2 π * (1.5*f _Wob) * t}), with beginning as the MSK mark; Second NWL is frequency f _WobSine wave (cos{2 π * f _Wob* MSK mark t}), and successively; And the 3rd NWL is frequency 1.5*f _WobSine wave (cos{2 π * (1.5*f _Wob) * t}), with end as the MSK mark.

Fig. 2 shows the definition of sawtooth wave.The method of HMW modulation is each time with some sawtooth waves (Sawtooth Wobbles, STW) the dull wave MW of replacement equal number.Each sawtooth wave STW is made up of the sinusoidal wave institute of basic cosine wave (CW) and two frequencys multiplication:

Cos{2 π * f _Wob* t} ± a*sin{2 π * (2*f _Wob) * t}, wherein a=0.25.

This cosine wave (CW) by basic frequency with and the approximate a kind of sawtooth wave of waveform formed of second harmonic, therefore the wave that method produced with the HMW modulation is called the sawtooth wave."+" or "-" number then produced inclination to the left or to the right (inclination), and wherein "+" number is used to represent bit value (bit value) " 1 ", and "-" number is used to represent bit value " 0 ".

Fig. 3 shows the framework of the ADIP information of Blue-Ray CD.The data that is recorded in CD must be aimed at (aligned) with the ADIP address of wave modulation.As shown in Figure 3,56 NWL are corresponding to two record material frames (recording frame), and are called as an ADIP unit (ADIP unit).

Fig. 4 shows the form of ADIP unit.As shown in Figure 4, the form of this ADIP unit has comprised:

Dull unit (monotone unit): comprise a MSK mark (MM), and 53 dull waves (MW);

Reference unit (reference unit): comprise a MSK mark (MM), 15 dull waves (MW), 37 sawtooth waves (STW) and 1 dull wave (MW);

Lock unit 0 (sync_0 unit): comprise a MSK mark (MM), 13 dull waves (MW), 1 MSK mark (MM), 7 dull waves (MW), 1 MSK mark (MM) and 27 dull waves (MW);

Lock unit 1 (sync_1 unit): comprise a MSK mark (MM), 15 dull waves (MW), 1 MSK mark (MM), 7 dull waves (MW), 1 MSK mark (MM) and 25 dull waves (MW);

Lock unit 2 (sync_2 unit): comprise a MSK mark (MM), 17 dull waves (MW), 1 MSK mark (MM), 7 dull waves (MW), 1 MSK mark (MM) and 23 dull waves (MW);

Lock unit 3 (sync_3 unit): comprise a MSK mark (MM), 19 dull waves (MW), 1 MSK mark (MM), 7 dull waves (MW), 1 MSK mark (MM) and 21 dull waves (MW);

Bit data 1 (data_1 unit): comprise a MSK mark (MM), 9 dull waves (MW), 3 dull waves (MW), 1 MSK mark (MM), 37 sawtooth waves (STW) and 1 dull wave (MW);

Bit data 0 (data_0 unit): comprise a MSK mark (MM), 11 dull waves (MW), 1 dull wave (MW), 1 MSK mark (MM), 37 sawtooth waves (STW) and 1 dull wave (MW).

So, can locate unit according to the form of above-mentioned ADIP unit and go out ADIP address on the discs.So in order correctly to judge the form of ADIP unit, right judgement sawtooth wave (STW) is that bit value " 1 " or " 0 " are very important subjects under discussion.

Summary of the invention

Because the problems referred to above the purpose of this invention is to provide a kind of sawtooth wave bit value testing circuit and correctly detect sawtooth wave bit value.

For reaching above-mentioned purpose, a kind of sawtooth wave bit value testing circuit of the present invention is that to be used for detecting a basic frequency be f _WobThe bit value of sawtooth wave of wave signal, it is characterized in that this testing circuit comprises:

One first bandpass filter, its centre frequency are 2*f _Wob, be to receive and filter described wave signal, and produce first filtering signal;

One second bandpass filter, its centre frequency are f _Wob, be to receive and filter described wave signal, and produce second filtering signal;

One first comparer is more described first filtering signal and a reference voltage, and produces two frequency-doubled signals;

One second comparer is more described second filtering signal and a reference voltage, and produces basic signal frequently;

One delay cell is to receive described basic frequency signal, and output delay signal after the delay preset delay time; And

One sampling unit be to serve as sampling clock pulse described two frequency-doubled signals of taking a sample with described inhibit signal, and the output sampling value is as the bit value of described sawtooth wave.

Described sawtooth wave bit value testing circuit, it is characterized in that: described preset delay time is 1/ (8*f _Wob) cycle.

The invention has the advantages that:

Sawtooth wave bit value testing circuit provided by the present invention can correctly detect sawtooth wave bit value.

Describe sawtooth wave bit value testing circuit of the present invention in detail below with reference to accompanying drawing.

Description of drawings

Fig. 1 shows the definition of MSK mark.

Fig. 2 shows the definition of sawtooth wave.

Fig. 3 shows the framework of the ADIP information of Blue-Ray CD.

Fig. 4 shows the form of ADIP unit.

Fig. 5 is a sawtooth wave bit value testing circuit of the present invention.

The waveform synoptic diagram that the emulation of Fig. 6 A-6E demonstration sawtooth wave bit value testing circuit of the present invention institute is come out, wherein Fig. 6 A is that wave signal, Fig. 6 B are that second filtering signal, Fig. 6 C are that first filtering signal and Fig. 6 E are two frequency-doubled signals for basic signal, Fig. 6 D frequently.

Fig. 7 A-7D shows that bit value is at 0 o'clock, the portion waveshape of sawtooth wave bit value testing circuit of the present invention institute emulation, and wherein Fig. 7 A is that two frequency-doubled signals and Fig. 7 D are bit value for basic signal frequently, Fig. 7 B signal, Fig. 7 C after for basic signal delay frequently.

Fig. 8 A-8D shows that bit value is at 1 o'clock, the portion waveshape of sawtooth wave bit value testing circuit of the present invention institute emulation, its midway 8A be that two frequency-doubled signals and Fig. 8 D are bit value for basic signal frequently, Fig. 8 B signal, Fig. 8 C after for basic signal delay frequently.

Embodiment

Fig. 5 is a sawtooth wave bit value testing circuit of the present invention.As shown in the drawing, sawtooth wave bit value testing circuit 50 of the present invention comprises first bandpass filter 51, second bandpass filter 52, one first comparer 53, one second comparer 54, a delay cell 55 and a sampling unit 56.

The centre frequency of first bandpass filter 51 is the basic frequency f of wave signal _WobTwice, and produce first filtering signal; And the centre frequency of second bandpass filter 52 is the basic frequency f of wave signal _Wob, and produce second filtering signal.Therefore, after wave signal was through first bandpass filter 51, the composition of basic frequency was filtered, and only kept the composition of two frequencys multiplication, that is:

±a*sin{2π*(2*f _wob)*t} ...(5)

And after wave signal was through second bandpass filter 52, the composition of two frequencys multiplication was filtered, and only kept the composition of basic frequency, that is:

cos{2π*f _wob*t} ...(6)

First comparer 53 is two frequency-doubled signals that first filtering signal converted to square wave, and second comparer 54 is the basic frequency signals that second filtering signal converted to square wave.First comparer 53 and second comparer 54 can be cutters, that is when the position of input signal standard is higher than reference voltage, then export H, otherwise then export L.Delay cell 55 receives basic signal frequently, and postpones a preset delay time, for example in the 1/8 basic cycle of signal frequently.56 of sampling units are to be trigger pip two frequency-doubled signals of taking a sample with basic frequency signal, and the bit value of output sawtooth wave.Sampling unit 56 can be trigger, or other can reach the circuit of identical function.

Because two frequency-doubled signals can be considered the sawtooth wave signal, so bit value is the phase place that the phase place of 1 two frequency-doubled signals can fall behind basic frequency signal, and therefore if signal delay is after a period of time frequently will be basic, and two frequency-doubled signals of being taken a sample should be 1.Otherwise bit value is that the phase place of 0 two frequency-doubled signals can the leading basic phase place of signal frequently, and therefore if signal delay is after a period of time frequently will be basic, and two frequency-doubled signals of being taken a sample should be 0.So what sawtooth wave bit value testing circuit of the present invention can be simply also correct produces sawtooth wave bit value according to wave signal.

The waveform synoptic diagram that Fig. 6 A-6E comes out for the emulation of sawtooth wave bit value testing circuit of the present invention institute, wherein Fig. 6 A is that wave signal, Fig. 6 B are that second filtering signal, Fig. 6 C are that first filtering signal and Fig. 6 E are two frequency-doubled signals for basic signal, Fig. 6 D frequently.As shown in Figure 6A, this wave signal is the sawtooth wave that is tilted to the right, so the bit value of this sawtooth wave should be 1.Second filtering signal of Fig. 6 B is with the filtered cosine wave (CW) of the wave signal of Fig. 6 A by second bandpass filter 52.The basic frequency signal of Fig. 6 C is with the square-wave signal after the cutting of second filtering signal.So shown in Fig. 6 C, this basic frequency of signal frequently is basic frequency f _WobAnd Fig. 6 D first filtering signal is with the filtered cosine wave (CW) of the wave signal of Fig. 6 A by first bandpass filter 51.Two frequency-doubled signals of Fig. 6 E are square waves that first filtering signal with Fig. 6 D is cut.So shown in Fig. 6 E, the frequency of this two frequency-doubled signal is the twice 2*f of basic frequency _Wob

Fig. 7 shows that bit value is at 0 o'clock, the portion waveshape of sawtooth wave bit value testing circuit of the present invention institute emulation, and wherein Fig. 7 A is that two frequency-doubled signals and Fig. 7 D are bit value for basic signal frequently, Fig. 7 B signal, Fig. 7 C after for basic signal delay frequently.As shown in the drawing, because the bit value of the sawtooth wave that is detected is 0, so shown in Fig. 7 A and Fig. 7 C, the phase place of the basic frequency signal of the leading Fig. 7 A of phase place of two frequency-doubled signals of Fig. 7 C.Therefore,, the positive edge of the signal after this delay two frequency-doubled signals of taking a sample can be utilized, 0 bit value signal can be produced as long as basic signal is frequently postponed a little.

Fig. 8 shows that bit value is at 1 o'clock, the portion waveshape of sawtooth wave bit value testing circuit of the present invention institute emulation, and wherein Fig. 8 A is that two frequency-doubled signals and Fig. 8 D are bit value for basic signal frequently, Fig. 8 B signal, Fig. 8 C after for basic signal delay frequently.As shown in the drawing, because the bit value of the sawtooth wave that is detected is 1, so shown in Fig. 8 A and Fig. 8 C, the phase place of the basic frequency signal of phase lag Fig. 8 A of two frequency-doubled signals of Fig. 8 C.Therefore,, the positive edge of the signal after this delay two frequency-doubled signals of taking a sample can be utilized, 1 bit value signal can be produced as long as basic signal is frequently postponed a little.

Though more than with embodiment the present invention is described, therefore do not limit scope of the present invention, only otherwise break away from main idea of the present invention, the sector person can carry out various distortion or change.

Claims (2)

1, a kind of sawtooth wave bit value testing circuit is that to be used for detecting a basic frequency be f _WobThe bit value of sawtooth wave of wave signal, it is characterized in that this testing circuit comprises:

One first bandpass filter, its centre frequency are 2*f _Wob, be to receive and filter described wave signal, and produce first filtering signal;

One second bandpass filter, its centre frequency are f _Wob, be to receive and filter described wave signal, and produce second filtering signal;

One first comparer is more described first filtering signal and a reference voltage, and produces two frequency-doubled signals;

One second comparer is more described second filtering signal and a reference voltage, and produces basic signal frequently;

One delay cell is to receive described basic frequency signal, and output delay signal after the delay preset delay time; And

One sampling unit be to serve as sampling clock pulse described two frequency-doubled signals of taking a sample with described inhibit signal, and the output sampling value is as the bit value of described sawtooth wave.

2, sawtooth wave bit value testing circuit according to claim 1, it is characterized in that: described preset delay time is 1/ (8*f _Wob) cycle.

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