JP2566332B2 - Peak level detecting device in optical disk reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides an optimum recording level setting when recording music information reproduced by an optical disk reproducing device such as a CD player using an external audio device. The present invention relates to a peak level detection device that detects the maximum output value of a reproduced signal at high speed.

[Prior Art] When recording music information or the like reproduced by an optical disk reproducing apparatus using a tape recorder or the like connected to the apparatus, the optical disk reproducing apparatus can preset an optimum recording level. For this purpose, a peak level detection device in a constant linear velocity (CLV) type optical disc reproducing device usually kicks the reproducing means arranged facing the optical disc from the inner circumference side to the outer circumference side. While jumping, the maximum output value (hereinafter referred to as a peak level) of the reproduced signal that is optically reproduced is detected.

Specifically, the kick amount for jumping the reproducing means is set to a constant value for several tens of tracks, and the subcode information of the jump destination track is read to confirm the track position. Then, in the track to which the jump is made, a reproduction signal is extracted for a predetermined time, and a peak level is detected from the extracted reproduction signal. For example, if the kick amount is set to 30 tracks for a compact disk (hereinafter, referred to as a CD) with a recording time of 75 minutes, the peak level detection time is about 1 minute, and A recording device such as a tape recorder stands by during that time.

[Problems to be Solved by the Invention]

However, in the conventional peak level detecting device in the above-mentioned optical disk reproducing device, since the kick amount is constant, the probability that the peak level is missed becomes higher toward the outer peripheral side. In the case of a CD player, the relational expression between the playing time (hereinafter referred to as the absolute playing time) T (s) based on the recording start position on the innermost side of the CD and the disc radius R (m) is PVT = It is expressed as π (R ² −R ₀ ² ). However, P: track pitch (m / line), V: linear velocity (m / s), R ₀ : recording start radius on the innermost circumference side (m). Assuming that the kick amount is Δm (lines / time), the distance ΔR (m / time) that the optical pickup as a reproducing means moves in the radial direction of the disc by a kick jump is ΔR = P · Δ
m (however, ΔR is also constant because Δm is set to be constant in the prior art). While the optical pickup jumps a distance ΔR in the radial direction of the disc, the amount of information (hereinafter, referred to as jump information amount) ΔT (s / time) that is passed without being reproduced is the disc radius R + Δ.
Can absolute playing time at the position of R T _R 'represent the difference between the absolute performance time T _R at the position of the disk radius R. That is, from the equation, T = π (R ² −R ₀ ² ) / PV, so ΔT = T _R ′ −T _R = π {(R + ΔR) ² −R ₀ ² } / PV −π (R ² − R ₀ ² ) / PV = π (2R + ΔR) ΔR / PV ...... From the formula, the relationship ΔT∝R is derived. That is, as shown in FIG. 4, the jump information amount ΔT increases as the disc radius R increases. In other words, there is a higher probability that the peak level of the reproduction signal will be missed as it approaches the outer circumference of the disc. According to the CD standard, the recording start radius R ₀ = 25 × 10 ^-3 (m) on the innermost side and the recording end radius R _e = 58 × 10 ^-3 (m) on the outermost side, so R _e / R ₀ = 58/25 = 2.32. From this, the probability of missing the peak level per kick jump near the outermost circumference of the CD is
It has a problem that it is about 2.3 times as large as the vicinity of the innermost circumference.

It is an object of the present invention to make the jump information amount ΔT per kick jump uniform for an optical disc controlled to have a constant linear velocity, and to improve the reliability of the detected peak level. It is to provide a detection device.

[Means for solving the problem]

In order to solve the above-mentioned problems, the peak level detecting device in the optical disk reproducing device according to the present invention has a maximum output of a reproduction signal obtained by optically reproducing continuous information digitally recorded on the optical disk, for example, music information. In a peak level detecting device in an optical disc reproducing device of a constant linear velocity control system for detecting a value, a reproducing position detecting device such as a track position detecting circuit for detecting reproducing position information of an reproducing device, for example, an optical pickup, which is arranged to face the optical disc, An instruction to detect the maximum output value of the reproduction signal is received from the outside, a detection command is output to the optical disc reproducing device, and when the reproducing means makes a kick jump, the information amount contained in the plurality of jumped tracks is recorded on the optical disc. Set it to a certain fixed value regardless of the position, and And control means for example CD controller to execute the predetermined time playback operation in pump destination track, with respect to the fixed value set by the control means,
Kick amount calculation means for calculating the kick amount of the reproduction means based on the reproduction position information, for example, a kick amount calculation circuit, and kick pulse generation means for generating a kick pulse having a pulse width according to the obtained kick amount, for example, kick pulse generation It is characterized in that it is provided with a circuit and a storage means for storing the maximum output value data of the reproduction signal for each kick jump, for example, a peak data memory.

[Work]

According to the above configuration, when the control means inputs the instruction to detect the maximum output value of the reproduction signal, the amount of information contained in the plurality of jumped tracks when the reproduction means arranged opposite to the optical disc makes a kick jump. Is set to a predetermined constant value regardless of the position of the optical disc. The kick amount calculation means determines the kick amount according to the reproduction position of the reproduction means on the basis of the information amount set to a constant value and the reproduction position information of the reproduction means detected by the reproduction position detection means according to the command of the control means. Calculate The kick pulse generation means generates a kick pulse having a pulse width according to the kick amount input from the kick amount calculation means. The kick jump of the reproducing means is controlled based on the generated kick pulse. Further, the control means causes the optical disc reproducing apparatus to execute a reproducing operation for a predetermined time on the track to which the jump is made, and the storage means stores the maximum output value data of the reproduced signal for each kick jump.

As a result, the amount of information contained in a plurality of jumped tracks is constant regardless of the reproduction position of the reproduction means, regardless of whether it is on the inner or outer circumference side of the optical disc, and the reliability of the detected maximum output value is high. The property is improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

As shown in FIG. 2, the optical disc reproducing apparatus according to the present invention includes an optical pickup 1 arranged opposite to an optical disc (not shown) as a reproducing unit. The optical pickup 1 is connected to a synchronization detection / demodulation circuit 2 and It is connected to a driver 6 that drives the optical pickup 1 for tracking based on a command from the servo control unit 7. The digital signal processing unit 5 includes a PLL (Phase Locked Loop) including a voltage controlled oscillator (CD crystal) 3, a synchronization detection / demodulation circuit 2, and an error correction / detection circuit 4. The RF signal output from the optical pickup 1 is supplied to a synchronization detection / demodulation circuit 2, and bit synchronization is maintained based on a clock generated by a PLL including a voltage controlled oscillator 3. Further, the RF signal is EFM demodulated and 14 channel bits are converted into 8 data bits. After the EFM demodulated data is frame-synchronized and the code error is corrected by the error correction / detection circuit 4,
The audio signal is converted into an analog signal by the D / A converter 8. The servo control unit 7 outputs a clock generated by the digital signal processing unit 5 via a switch SW connected to a terminal 9 at the time of an access operation to a desired track, a fast-forward reproduction operation, or a pause operation. The optical pickup 1 performs a kick jump operation by inputting and supplying a kick pulse having a predetermined width generated based on a clock to the driver 6. For example, during a fast-forward playback operation, the optical pickup 1 is
A kick jump is performed every ten jumps, and a control is performed so that a reproduction operation for a short period of time is performed on the jumped track.

The peak level detecting device 11 according to the present invention includes a track position detecting circuit 12 as a reproducing position detecting means, a kick amount calculating circuit 13 as a kick amount calculating means, and a CD as a control means.
A controller 14, a kick pulse generation circuit 15 as kick pulse generation means, an A / D converter 16, and a peel data memory 17 as storage means are provided. The track position detection circuit 12 is supplied with the subcode data from the synchronization detection / demodulation circuit 2, and detects the absolute playing time T at the reproduction position of the optical pickup 1. The absolute performance time T is, for example, when music information is recorded on an optical disc,
This shows the total playing time from the memory start position on the innermost circumference side. The CD controller 14 receives various operation instructions input from the operation key group 19, outputs operation instructions to the optical disk reproducing device, and controls the entire system. Further, when the controller 14 receives an instruction to search (detect) the peak level of the audio signal output from the D / A converter 8 via the peak search key of the operation key group 19, the optical pickup 1 makes a kick jump. At this time, the amount of information contained in the jumped tracks (hereinafter referred to as the amount of jump information) is set to a predetermined constant value regardless of the position on the optical disc. In addition, the CD controller 14 switches the switch SW from the terminal 9 to the terminal 10 at the time of the peak level search so that the servo control unit 7 is set to the peak level detecting device.
11 or by causing the optical disk reproducing apparatus to perform a reproducing operation for a predetermined time on the jump destination track, or based on the subcode information supplied via the track position detecting circuit 12, the absolute playing time T is displayed on the display unit 18. Or display the song number.

The kick amount calculation circuit 13, which is the most important configuration requirement of the present invention, determines the kick amount of the optical pickup 1 according to the disc radius with respect to the constant value of the jump information amount set by the CD controller 14. Calculate The kick pulse generation circuit 15 generates a kick pulse based on the calculation result of the kick amount calculation circuit 13 and the clock generated by the digital signal processing unit 5. The generated kick pulse is transmitted to the servo control unit 7 via the switch SW connected to the terminal 10.
Is supplied to. The servo control unit 7 drives the driver 6 based on the supplied kick pulse. On the other hand, A /
The D converter 16 is an audio signal generated by the D / A converter 8 (reproduced for a predetermined time on the jump destination track).
Is input and converted into a digital signal. The peak data memory 17 reads and stores the peak level from the digital signal.

The calculation of the kick amount performed by the kick amount calculation circuit 13 will be described in detail.

First, the absolute performance time T (seconds) is the disk radius R (m)
And a function represented by the following equation.

PVT = π (R ² −R ₀ ² ), where P: track pitch (m / line), V: linear velocity (m / line)
s), R ₀ : Recording start radius (m) on the innermost circumference side.

From the equation, R ² = PVT / π + R ₀ ² Therefore, R = (PVT / π + R ₀ ² ) ^1/2 ...... The number of tracks included in the disk radius R, that is, the absolute performance time T is m (pieces) Then, R = P · m + R ₀ ……, so from the formula, P · m + R ₀ = (PVT / π + R ₀ ² ) ^1/2 Therefore, m = {(PVT / π + R ₀ ² ) ^1/2 −R _The expression ₀ } / P represents the relationship between the absolute performance time T and the number m of tracks included in the absolute performance time T (disk radius R). Here, based on the CD standard, P = 1.6 × 10 ⁻⁶ (m /
Book), V = 1.25 (m / s), R ₀ = 25 × 10 ⁻³ (m), and π = 3.14, and the information amount that the optical pickup passes without reproducing, that is, the jump information amount ΔT is absolute. It is set to a fixed value of, for example, 60 seconds after being converted into the playing time. As a result, when the peak level search instruction is given, the optical pickup 1 converts the absolute performance time T into T = 60 → 120.
→ 180 → …… You can perform a kick jump and perform playback for a specified time at the jumped track position. Table 1 shows specific numerical values of the absolute performance time T and the number of tracks m calculated according to the equation.

In Table 1, the kick amount Δm _n (number / time) is Δm _n = m _n −m _n−1
(N = 1, 2, ...), and shows the number of tracks to jump when the jump information amount ΔT is constant. As shown in FIG. 3, the kick amount Δm _n gradually decreases as the disk radius R increases and approaches the outer peripheral side.

Kick pulse width W output by the kick pulse generation circuit 15
Let k be the kick energy required to cause the optical pickup 1 to perform a kick jump for one track, then W _n ∝k (m _n −m _n−1 ) = kΔm _n (n = 1, 2 ,…)…… It can be expressed as. For example, when the peak level search is performed from the recording start radius R ₀ (absolute performance time T ₀ ) on the innermost circumference side, the kick pulse generation circuit 15 supplies the servo control unit 7 with a pulse width W ₁ = kΔm ₁ = 470 k. The kick pulse that the user has will be output.

The operation of the peak level search will be described below based on the flowchart of FIG.

First, various instructions are input from the operation key group 19 (Step 1: hereinafter, described as S1). In S2, unless an instruction is input from the peak level search key, various normal operations are executed under the control of the CD controller 14 (S3). When the peak level search instruction is input, the CD controller 14 sets the jump information amount ΔT to a constant value (S4). Next, the optical pickup 1 is caused to perform a reproducing operation for a predetermined time, and the track position detection circuit 12 reads the absolute performance time T from the subcode data supplied from the digital signal processing section 5, and the disc of the optical pickup 1 is read. The position is detected (S5). The kick amount calculation circuit 13 executes the calculation represented by the equation to obtain the kick amount Δm _n based on the disc position as shown in Table 1 (S6). The kick pulse generation circuit 15 generates a kick pulse having a kick pulse width W based on the kick amount Δm _n (S7) and outputs it to the servo control unit 7 (S8).
The driver 6 drives the optical pickup 1 based on the output of the servo control unit 7 to perform a kick jump. The optical pickup 1 performs reproduction for a predetermined time on the jump destination track, and the audio data processed through the digital signal processing unit 5 and the D / A converter 8 is A / D converter 1
After being converted into a digital signal in 6, one peak level is read and stored in the peak data memory 17 for one kick jump (S9, S10). After this, if the instruction to stop the peak level search is not inserted in the middle, the process returns to S5, and 1 is passed from the inner circumference to the outer circumference of the disc.
The street peak level search is repeated. When the peak level of the required music information is detected and an instruction to stop the peak level search is input, the process moves from S11 to S12,
A normal recording / reproducing operation can be performed.

〔The invention's effect〕

As described above, the peak level detecting device in the optical disc reproducing device according to the present invention detects the reproducing position information of the reproducing device arranged facing the optical disc, and the maximum output value of the reproducing signal of the continuous information. Is received from the outside, a detection command is output to the optical disc reproducing device, and when the reproducing means kick-jumps, the amount of information contained in the jumped tracks is determined by a predetermined amount regardless of the position on the optical disc. Set to a fixed value,
Control means for causing the optical disk reproducing apparatus to execute a reproducing operation for a predetermined time on the jump destination track, and a kick for calculating the kick amount of the reproducing means based on the reproduction position information with respect to the above-mentioned constant value set by the control means. Quantity calculation means,
With a configuration provided with a kick pulse generating means for generating a kick pulse having a pulse width according to the obtained kick amount, and a storage means for storing the maximum output value data of the reproduced signal for each kick jump. is there.

Therefore, when the kick jump of the reproducing means is executed, whether it is on the inner circumference side or the outer circumference side of the optical disc,
The amount of information contained in the jumped tracks is constant regardless of the reproduction position of the reproduction means. As a result, the probability that the true maximum output value is detected from the reproduction signal extracted from the jump destination track is increased, and the reliability of the detected maximum output value is improved.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a flowchart showing a kick jump control operation in the peak level detecting device. FIG. 2 is a block diagram showing the configuration of the peak level detecting device in the optical disk reproducing device. FIG. 3 is a graph showing the disc radius dependence of the kick amount. FIG. 4 shows a conventional example and is a graph showing the disc radius dependence of the amount of jump information. 1 is an optical pickup (reproducing means), 11 is a peak level detecting device, 12 is a track position detecting circuit (reproducing position detecting means), 13 is a kick amount calculating circuit (kick amount calculating means), 14
Is a CD controller (control means), 15 is a kick pulse generation circuit (kick pulse generation means), and 17 is a peak data memory (storage means).

Claims (1)

(57) [Claims] 1. A peak level detecting device in an optical disk reproducing apparatus of a constant linear velocity control system for detecting a maximum output value of a reproduced signal obtained by optically reproducing continuous information digitally recorded on an optical disk. A reproduction position detection means for detecting reproduction position information of reproduction means arranged opposite to the reproduction means, an instruction for detecting a maximum output value of the reproduction signal is externally received, and a detection instruction is output to an optical disk reproduction apparatus;
When the reproducing means makes a kick jump, the amount of information contained in the jumped tracks is set to a predetermined constant value irrespective of the position on the optical disk, and the optical disk reproducing apparatus further sets the predetermined time on the jump destination track. Depending on the control means for executing the reproduction operation, the kick amount calculation means for calculating the kick amount of the reproduction means based on the reproduction position information with respect to the above-mentioned constant value set by the control means, and the obtained kick amount. In the optical disc reproducing apparatus, a kick pulse generating means for generating a kick pulse having a different pulse width and a storage means for storing the maximum output value data of the reproduction signal for each kick jump are provided. Peak level detector.