JP2010027139A - Decoding device and method, recording and reproducing device and method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the scale of a circuit for performing soft input and soft output decoding. <P>SOLUTION: Fig. 4 shows integrated trellis expressions for three hours of a PR12221 channel. Further, soft information corresponding to each branch of the integrated trellis expression is calculated by adding soft information for three hours in trellis expression of Fig.3 (not shown). For example, in the integrated trellis expression, soft information γ(0, 0) corresponding to the branch of transition from a state s0 to s0 is calculated by adding together soft information γa(0, 0) corresponding to the branch of transition from the state s0 of current time in the trellis expression of Fig.3 to a state s0 after one hour, soft information γb(0, 0) corresponding to the branch of transition to a state s0 after one hour further, and soft information γc(0, 0) corresponding to the branch of transition to a state s0 after one hour further. The present invention is applicable to, for example, a device for recording and reproducing to and from a Blu-ray disk. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a decoding device, a decoding method, a recording / reproducing device, a recording / reproducing method, and a program, and in particular, a decoding device, a decoding method, and a decoding method that can reduce the scale of a circuit that performs decoding processing including soft input / soft output decoding, The present invention relates to a recording / reproducing apparatus, a recording / reproducing method, and a program.

  When recording a signal on a recording medium such as a magnetic disk or an optical disk, the signal to be recorded is modulated and encoded so that the amplitude control of the read signal and clock reproduction operate normally during reproduction. The obtained encoded signal is recorded on a recording medium through a PR (Partial Response) communication path. For reproduction from the recording medium, the original waveform is reproduced in consideration of the characteristics of the recording medium, such as the read signal receiving interference from the adjacent signal, and the original waveform is reproduced. A reproduction process such as PRML (Partial Response Maximum-Likelihood) that outputs the most probable reproduction signal is used based on the characteristics of the waveform.

  For example, when a signal is recorded on a high-density optical disk typified by a BD (Blu-ray Disc), a 17PP (Parity Preserve / Prohibit RMTR (Repeated Minimum Transition Runlength)) code is used as a modulation encoding method. In this 17PP code, as shown in Patent Document 1, a complicated variable length coding table is used. The PR12221 channel is used as the PR communication path.

US Pat. No. 6,496,541 B1

  By the way, when reproducing a signal recorded using the 17PP code and the PR1221 channel as described above, the signal read out by the PR communication path of the PR12221 channel is soft input soft output based on the trellis expression corresponding to the PR12221 channel. Decoding is performed, and 17PP Viterbi decoding is performed in a state where soft information for each branch of the trellis expression obtained as a result is held in the memory.

  Therefore, when the number of branches of the trellis expression is large, such as the combination of the 17PP code and the PR12221 channel, the number of memories that hold soft information is also increased according to the number of branches of the trellis expression. It gets bigger.

  The present invention has been made in view of such a situation, and makes it possible to reduce the scale of a circuit that performs soft input / soft output decoding.

The demodulating device according to the first aspect of the present invention includes an equalizing unit that equalizes a signal that has been modulated and encoded according to a predetermined modulation code scheme in accordance with a predetermined PR characteristic, and the equalized signal. A trellis expression corresponding to the predetermined PR characteristic, which is a state transition table representing an encoding process at each time, developed in time series, and based on the obtained trellis expression, soft input soft output decoding is obtained. By executing a PR-SISO decoding unit that calculates soft information corresponding to each branch of the trellis expression, an integration unit that integrates the calculated soft information for a predetermined time, and the integrated Based on a trellis expression corresponding to the predetermined modulation code scheme and holding means for holding soft information, and before the modulation and coding by the predetermined modulation code scheme using the held integrated soft information Original signal of Modulation and decoding means for demodulating the signal.

  The predetermined PR characteristic may be a PR12221, PR1221 or PR121 channel.

  The predetermined modulation and coding scheme may be a 17PP code.

  The integration unit can integrate soft information corresponding to each branch of the trellis expression corresponding to the predetermined PR characteristic every three times.

  The demodulation method according to the first aspect of the present invention is a demodulation method for a demodulator that demodulates an original signal from a signal that has been modulated and encoded by a predetermined modulation code method. A state transition table representing an encoding process at each time corresponding to the predetermined PR characteristic based on the equalized signal and equalized in accordance with the predetermined PR characteristic. Is calculated along the time series, and soft information corresponding to each branch of the trellis expression is calculated by executing soft input / soft output decoding based on the obtained trellis expression. Integrated the soft information for a predetermined time, retains the integrated soft information, and holds the integrated soft information based on a trellis expression corresponding to the predetermined modulation code scheme. Using includes the step of demodulating the original signal before being modulated encoded by the predetermined modulation encoding scheme.

  The program according to the first aspect of the present invention is equalized with equalization means for equalizing a computer in accordance with a predetermined PR characteristic, a signal modulated and encoded by a predetermined modulation code method. Based on the signal, a trellis expression corresponding to the predetermined PR characteristic and expanding a state transition table representing an encoding process at each time is developed along a time series, and soft input softening is performed based on the obtained trellis expression. By executing output decoding, PR-SISO decoding means for calculating soft information respectively corresponding to each branch of the trellis expression and integration means for integrating the calculated soft information for a predetermined time are integrated. Based on the trellis expression corresponding to the predetermined modulation code scheme, the holding means for holding the soft information and modulation coding by the predetermined modulation code scheme using the held integrated soft information It functions as modulation and decoding means for demodulating the original signal before being processed.

  According to the first aspect of the present invention, a signal modulated and encoded by a predetermined modulation code scheme is equalized corresponding to a predetermined PR characteristic, and based on the equalized signal, the predetermined PR A trellis expression corresponding to a characteristic and representing a state transition table representing an encoding process at each time is developed along a time series, and soft input / soft output decoding is performed based on the obtained trellis expression. Soft information corresponding to each branch of the trellis expression is calculated. Further, the calculated soft information is integrated and stored for a predetermined time, and based on the trellis expression corresponding to the predetermined modulation code scheme, the stored soft information is used to store the predetermined soft information. The original signal before being modulated and encoded by the modulation code method is demodulated.

  The recording / reproducing apparatus according to the second aspect of the present invention comprises: encoding means for modulating and encoding an input signal by a predetermined modulation encoding method to generate an encoded signal; and recording means for recording the encoded signal on a recording medium And reading the signal recorded on the recording medium, equalizing means for equalizing the read signal corresponding to a predetermined PR characteristic, and based on the equalized signal, the predetermined PR characteristic. The trellis expression is obtained by obtaining a corresponding trellis expression in which a state transition table representing an encoding process at each time is expanded along a time series, and performing soft input soft output decoding based on the obtained trellis expression. PR-SISO decoding means for calculating soft information corresponding to each of the branches, integration means for integrating the calculated soft information for a predetermined time, holding means for holding the integrated soft information, The predetermined Modulation decoding means for demodulating the original signal before being modulated and encoded by the predetermined modulation code method, using the integrated soft information held based on the trellis expression corresponding to the modulation code method; Including.

  A recording / reproducing method according to a second aspect of the present invention is a recording / reproducing method of a recording / reproducing apparatus that records and reproduces an input signal on a recording medium. Modulating and generating an encoded signal, recording the encoded signal on a recording medium, reading the signal recorded on the recording medium, equalizing the read signal corresponding to a predetermined PR characteristic, Based on the equalized signal, a trellis expression corresponding to the predetermined PR characteristic and representing a state transition table representing an encoding process at each time is developed along a time series, and based on the obtained trellis expression Soft information corresponding to each branch of the trellis expression is calculated by performing soft input / soft output decoding, and the calculated soft information is integrated for a predetermined time, and the integrated soft information is calculated. And based on the trellis representation corresponding to the predetermined modulation code scheme, the original signal before being modulated and encoded by the predetermined modulation code scheme is obtained using the held integrated soft information. Demodulating.

  According to a second aspect of the present invention, there is provided a program for recording on a computer, encoding means for generating an encoded signal by modulating and encoding an input signal using a predetermined modulation encoding method, and recording the encoded signal on a recording medium. Means for reading the signal recorded on the recording medium, equalizing means for equalizing the read signal corresponding to a predetermined PR characteristic, and based on the equalized signal, the predetermined PR characteristic A trellis expression in which a state transition table representing an encoding process at each time corresponding to each time is expanded along a time series, and soft input / soft output decoding is performed based on the obtained trellis expression. PR-SISO decoding means for calculating soft information corresponding to each branch of the expression, integration means for integrating the calculated soft information for a predetermined time, and holding means for holding the integrated soft information And based on the trellis expression corresponding to the predetermined modulation code method, the original signal before being modulated and encoded by the predetermined modulation code method is demodulated using the held integrated soft information. It functions as a modulation decoding means.

  In the second aspect of the present invention, an input signal is modulated and encoded by a predetermined modulation encoding method to generate an encoded signal, and the encoded signal is recorded on a recording medium. Further, a signal recorded on the recording medium is read out, the read signal is equalized corresponding to a predetermined PR characteristic, and the predetermined PR characteristic is obtained based on the equalized signal. Corresponding, a trellis expression in which a state transition table representing an encoding process at each time is expanded along a time series is obtained, and soft input / soft output decoding is performed based on the obtained trellis expression, Soft information corresponding to each branch of the trellis expression is calculated. Further, the calculated soft information is integrated and stored for a predetermined time, and based on the trellis expression corresponding to the predetermined modulation code scheme, the stored soft information is used to store the predetermined soft information. The original signal before being modulated and encoded by the modulation code method is demodulated.

  According to the first aspect of the present invention, an original signal can be demodulated from a signal that has been modulated and encoded by a predetermined modulation code method.

  In addition, according to the first aspect of the present invention, the capacity of a memory that holds soft information can be reduced. Drunk and can reduce circuit scale.

  According to the second aspect of the present invention, the input signal can be recorded on the recording medium and reproduced.

  Further, according to the second aspect of the present invention, the capacity of the memory that holds the soft information can be reduced. Drunk and can reduce circuit scale.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 shows a configuration example of a recording / reproducing apparatus according to an embodiment of the present invention. The recording / reproducing apparatus 10 modulates and encodes a signal input from the previous stage (hereinafter referred to as an input signal) and records it on a recording medium, reads out the signal from the recording medium, reproduces the original signal, and obtains the result. Is output to the subsequent stage.

  The recording / reproducing apparatus 10 includes a 17PP encoding unit 11, a PR communication path 21, and a decoding unit 31.

  The 17PP encoding unit 11 performs modulation encoding on the input signal by referring to the internal encoding table 12, and outputs a variable-length encoded signal obtained as a result to the PR communication path 21.

  The PR communication path 21 includes a recording / playback unit 22 and an equalization processing unit 24, and performs recording / playback processing using a PR12221 channel recording / playback channel. The recording / reproducing unit 22 performs NRZI (non return to zero Inverted) encoding on the encoded signal input from the 17PP encoding unit 11 and records the resulting NRZI encoded signal on a removable recording medium 23 as mark edge recording. Record using the (Mark Edge Recording) method. Here, the recording medium 23 is assumed to be a high-density optical disc such as a Blu-ray disc, but is not limited thereto.

  Further, the recording / reproducing unit 21 reads out the NRZI encoded signal recorded on the recording medium 23 through the PR12221 channel and supplies it to the equalization processing unit 24. The equalization processing unit 24 performs PR equalization using waveform interference on the supplied NRZI encoded signal so as to obtain a predetermined target equalization characteristic, and supplies the result to the decoding unit 13.

  The decoding unit 31 includes a PR-SISO (Partial Response Soft-Input Soft-Output) decoding unit 32 and a 17PP-SISO decoding unit 34.

  The PR-SISO decoding unit 32, based on the NRZI coding and the PR12221 channel, from the signal supplied from the PR communication channel 12, the state transition table representing the encoding process at each time is developed along the time series. And soft information corresponding to each branch of the NRZI coding and the PR12221 channel trellis representation is calculated by executing soft input / soft output decoding based on the obtained NRZI coding and the trellis representation of the PR12221 channel. .

  The integration unit 33 built in the PR-SISO decoding unit 32 reduces the total number of soft information by integrating the NRZI encoding and the soft information for three times of the trellis expression of the PR12221 channel, thereby reducing the total number of soft information to the 17PP-SISO decoding unit. 34.

  The 17PP-SISO decoding unit 34 holds the soft information supplied from the integration unit 33 and integrated for three times in the built-in soft information memory 35. Further, the 17PP-SISO decoding unit 34 obtains a trellis representation of the 17PP code based on the coding table 12 built in the 17PP coding unit 11, and holds it in the soft information memory 35 based on the obtained trellis representation of the 17PP code. The soft decision Viterbi decoding is performed using the soft information thus obtained, and the reproduced signal obtained as a result is output to the subsequent stage.

  Here, a process of integrating the soft information for three times of the NRZI encoding and the trellis expression of the PR12221 channel by the integration unit 33 will be described.

  FIG. 2 shows one time of NRZI coding and trellis representation of the PR12221 channel. When a 17PP code is used for the modulation and coding scheme, NRZI encoding and the input to the PR12221 channel trellis are limited so that 1 is not continuous. Therefore, the number of states is 10 types from s0 to s9. The number is 16.

  For example, if the state at the current time (left side in the figure) is s0, when 0 is input, -8 is output, the state at the next time (right side in the figure) transitions to s0, and 1 is input. And -6 are output, and the state at the next time transitions to s1. If the state at the current time is s1, when 0 is input, -2 is output and the state at the next time transitions to s1. Note that 1 is not input when the current time state is s1 due to the restriction described above. When the current time state is s2, when 0 is input, +2 is output and the next time state transitions to s4. When 1 is input, 0 is output and the next time state transitions to s3. To do.

  When the state at the current time is s3, when 0 is input, 0 is output and the state at the next time transits to s7. Note that 1 is not input when the current time state is s3 due to the restriction described above. If the current time state is s4, when 0 is input, +6 is output and the next time state transitions to s9. When 1 is input, +4 is output and the next time state transitions to s8. To do. When the current time state is s5, when 0 is input, -6 is output and the next time state transitions to s0. When 1 is input, -4 is output and the next time state is s1. Transition to.

  When the state at the current time is s6, when 0 is input, 0 is output and the state at the next time transits to s2. Note that 1 is not input when the current time state is s6 due to the restriction described above. When the current time state is s7, when 0 is input, -2 is output and the next time state transitions to s5. When 1 is input, 0 is output and the next time state is s6. Transition. If the state at the current time is s8, when 0 is input, +2 is output and the state at the next time transitions to s7. Note that 1 is not input when the current time state is s8 due to the restriction described above. When the current time state is s9, when 0 is input, +8 is output and the next time state transitions to s9. When 1 is input, +6 is output and the next time state transitions to s8. To do.

  FIG. 3 shows a concatenation of the trellis representation for one time shown in FIG. 2 for three times.

  That is, for example, when the state at the current time (left side in the figure) is s0, when 0, 0, and 0 are sequentially input with the passage of time, −8, −8, and −8 are output in order, and 3 The state after the time (right side in the figure) transitions to s0. When the state at the current time is s0, when 0, 0, and 1 are sequentially input with the passage of time, -8, -8, and -6 are sequentially output, and the state after 3 hours transitions to s1. . When the state at the current time is s0, when 0, 1, 0 are sequentially input along with the passage of time, -8, -6, -2 are sequentially output, and the state after 3 hours transitions to s2. . When the state at the current time is s0, when 1, 0, 0 are sequentially input as time elapses, −6, −2, +2 are sequentially output, and the state after 3 hours transitions to s4. When the state at the current time is s0, when 1, 0, 1 are sequentially input as time passes, −6, −2, 0 are sequentially output, and the state after 3 hours transitions to s3.

  Also, for example, if the state at the current time is s1, if 0, 0, 0 are input in order with the passage of time, -2, +2, +6 are output in order, and the state after 3 hours transitions to s9 To do. When the current time state is s1, when 0, 0, and 1 are sequentially input as time passes, -2, +2, and +4 are sequentially output, and the state after 3 hours transitions to s8. If the state at the current time is s1, when 0, 1, 0 are input in order with the passage of time, -2, 0, 0 are output in order, and the state after 3 hours transitions to s7.

  Further, for example, when the state at the current time is s2, when 0, 0, 0 are input in order with the passage of time, +2, +6, +8 are output in order, and the state after 3 hours transitions to s9. . When the state at the current time is s2, when 0, 0, and 1 are sequentially input with the passage of time, +2, +6, and +6 are sequentially output, and the state after 3 hours transitions to s8. If the state at the current time is s2, when 0, 1, 0 are sequentially input as time elapses, +2, +4, +2 are sequentially output, and the state after 3 hours transitions to s7. When the state at the current time is s2, when 1, 0, 0 is input in order with the passage of time, 0, 0, -2 are output in order, and the state after 3 hours transitions to s5. When the state at the current time is s2, when 1, 0, 1 are input in order with the passage of time, 0, 0, 0 are output in order, and the state after 3 hours transitions to s6.

  The description of the case where the current time state is s3 to s9 is omitted.

  As is clear from FIG. 3, the number of branches in the trellis representation for three times of NRZI coding and PR12221 channel is 48. Therefore, the soft information corresponding to each branch for three times has 48 values.

  However, if FIG. 3 is reviewed again, it can be seen that there are 42 paths from 10 states at the current time to 10 states after 3 times by 3 transitions. This is because when the 17PP code is used for the modulation and coding scheme, the NRZI coding and the input to the trellis of the PR12221 channel are limited so that 1 is not continuous.

  Therefore, the NRZI coding shown in FIG. 3 and the PR12221 channel for three times, that is, the trellis representation of three transitions are integrated and expressed as one transition.

  FIG. 4 shows the NRZI coding shown in FIG. 3 and the trellis representation for three times of the PR12221 channel, which are expressed as a single transition. Therefore, the trellis expression of FIG. 4 (hereinafter referred to as an integrated trellis expression) is equivalent to the trellis expression shown in FIG.

  That is, in the integrated trellis expression of FIG. 4, for example, when the state at the current time (left side in the figure) is s0, when 3 bits 000 are input, three values “−8, −8, −8” are output. Then, the state transitions to state s0. When 3-bit 001 is input, three values “−8, −8, −6” are output and the state transitions to s1. When 3 bits 010 are input, the ternary values “−8, −6, −2” are output, and the state transitions to s2. When 3 bits 100 are input, ternary values “−6, −2, +2” are output, and the state transitions to s4. When 3 bits 101 are input, a ternary value “−6, −2, 0” is output and the state transitions to s3.

  When the state at the current time is s1, when 3 bits 000 are input, a ternary value “−2, +2, +6” is output and the state transits to state s9. When 3-bit 001 is input, the ternary values “−2, +2, +4” are output, and the state transitions to s8. When 3-bit 010 is input, a ternary value “−2, 0, 0” is output and the state transitions to s7.

  When the state at the current time is s2, when 3 bits 000 are input, a ternary value “+2, +6, +8” is output and the state transits to state s9. When 3-bit 001 is input, the three values “+2, +6, +6” are output, and the state transitions to s8. When 3-bit 010 is input, the three values “+2, +4, +2” are output, and the state transitions to s7. When 3 bits 100 are input, a ternary value “0, 0, −2” is output and the state transitions to s5. When 3 bits 101 are input, a ternary value “0, 0, 0” is output and the state transitions to s6.

  If the state at the current time is s3, when 3 bits 000 are input, a ternary value “0, -2, -6” is output and the state transitions to the state s0. When 3-bit 001 is input, the ternary values “0, −2, −4” are output, and the state transitions to s1. When 3-bit 010 is input, a ternary value “0, 0, 0” is output and the state transitions to s2.

  When the state at the current time is s4, when 3 bits 000 are input, the ternary value “+6, +8, +8” is output and the state transits to state s9. When 3-bit 001 is input, the three values “+6, +8, +6” are output, and the state transitions to s8. When the 3-bit 010 is input, the three values “+6, +6, +2” are output, and the state transitions to s7. When 3 bits 100 are input, ternary values “+4, +2, −2” are output, and the state transitions to s5. When 3 bits 101 are input, a ternary value “+4, +2, 0” is output and the state transitions to s6.

  When the state at the current time is s5, when 3 bits 000 are input, the three values “−6, −8, −8” are output and the state transitions to the state s0. When 3-bit 001 is input, three values “−6, −8, −6” are output, and the state transitions to s1. When 3-bit 010 is input, ternary values “−6, −6, −2” are output, and the state transitions to s2. When 3 bits 100 are input, ternary values “−4, −2, +2” are output and the state transitions to s4. When 3 bits 101 are input, a ternary value “−4, −2, 0” is output and the state transitions to s3.

  If the state at the current time is s6, when 3 bits 000 are input, a ternary value “0, +2, +6” is output and the state transits to state s9. When 3-bit 001 is input, the ternary values “0, +2, +4” are output, and the state transitions to s8. When 3 bits 010 is input, a ternary value “0, 0, 0” is output and the state transitions to s7.

  When the state at the current time is s7, when 3 bits 000 are input, a ternary value "-2, -6, -8" is output and the state transitions to the state s0. When 3-bit 001 is input, ternary values “−2, −6, −6” are output and the state transitions to s1. When 3 bits 010 are input, the ternary values “−2, −4, −2” are output, and the state transitions to s2. When 3 bits 100 are input, a ternary value “0, 0, +2” is output and the state transitions to s4. When 3 bits 101 are input, a ternary value “0, 0, 0” is output and the state transitions to s3.

  If the state at the current time is s8, when 3 bits 000 are input, a ternary value “+2, −2, −6” is output and the state transitions to the state s0. When 3-bit 001 is input, a ternary value “+2, −2, −4” is output and the state transitions to s1. When 3-bit 010 is input, a ternary value “+2, 0, 0” is output, and the state transitions to s2.

  If the state at the current time is s9, when 3 bits 000 are input, the three values “+8, +8, +8” are output and the state transitions to state s9. When 3-bit 001 is input, a ternary value “+8, +8, +6” is output and the state transitions to s8. When 3-bit 010 is input, a ternary value “+8, +6, +2” is output and the state transitions to s7. When 3 bits 100 are input, ternary values “+6, +2, −2” are output, and the state transitions to s5. When 3 bits 101 are input, a ternary value “+6, +2, 0” is output and the state transitions to s6.

  As described above, according to the integrated trellis expression, the number of branches is 42, so that the soft information corresponding to each branch can also have 42 values. As a result, as shown in FIG. 3, compared with the case where 48-value soft information corresponding to 48 branches is output to the 17PP-SISO decoding unit 34, the soft information built into the 17PP-SISO decoding unit 34 is increased. The capacity of the information memory 35 can be reduced.

  The soft information corresponding to each branch of the integrated trellis expression is calculated by adding the soft information for three times in the trellis expression of FIG.

For example, in the integrated trellis expression, the soft information γ (0, 0) corresponding to the branch that transitions from the state s0 to s0 is one hour after the current state s0 in the trellis expression of FIG. Soft information γa (0,0) corresponding to the branch transitioning to state s0, soft information γb (0,0) corresponding to the branch transitioning to state s0 one hour later, and a state one hour later It is calculated by adding the soft information γc (0, 0) corresponding to the branch transitioning to s0.
γ (0,0) = γa (0,0) + γb (0,0) + γc (0,0)

Further, for example, in the integrated trellis expression, the soft information γ (1, 7) corresponding to the branch that transitions from the state s1 to s7 is one time from the current state s1 in the trellis expression of FIG. The soft information γa (1, 2) corresponding to the branch transitioning to the later state s2, the soft information γb (2, 3) corresponding to the branch transitioning to the state s3 one hour later, and the one hour later It is calculated by adding the soft information γc (3, 7) corresponding to the branch transitioning to the state s7.
γ (1,7) = γa (1,2) + γb (2,3) + γc (3,7)

Further, for example, in the integrated trellis expression, the soft information γ (2,9) corresponding to the branch that transitions from the state s2 to s9 is one time from the current state s2 in the trellis expression of FIG. The soft information γa (2, 4) corresponding to the branch transitioning to the later state s4, the soft information γb (4, 9) corresponding to the branch transitioning to the state s9 one hour later, and the one hour later It is calculated by adding the soft information γc (9, 9) corresponding to the branch transitioning to the state s9.
γ (2,9) = γa (2,4) + γb (4,9) + γc (9,9)

  Next, playback processing by the recording / playback apparatus 10 will be described with reference to the flowchart of FIG.

  In step S <b> 1, the recording / playback unit 22 reads the encoded signal recorded on the recording medium 23 using the PR12221 channel, and supplies the read encoded signal to the equalization processing unit 24. In step S2, the equalization processing unit 24 performs PR equalization using waveform interference on the supplied encoded signal so as to obtain a predetermined target equalization characteristic, and the PR− of the decoding unit 31. This is supplied to the SISO decoding unit 32.

  In step S3, the PR-SISO decoding unit 32 obtains a trellis expression corresponding to the NRZI coding and the PR12221 channel based on the signal supplied from the equalization processing unit 24, and performs soft input based on the obtained trellis expression. By executing soft output decoding, soft information corresponding to each branch of NRZI coding and the trellis representation of the PR12221 channel is calculated.

  In step S4, the integrating unit 33 calculates soft information corresponding to each branch of the integrated trellis expression shown in FIG. 4 by integrating the soft information calculated in the process of step S3 for three times, The 17PP-SISO decoding unit 34 is supplied.

  In step S <b> 5, the 17PP-SISO decoding unit 34 holds the soft information corresponding to each branch of the integrated trellis expression supplied from the integration unit 33 in the soft information memory 35. Then, the 17PP-SISO decoding unit 34 obtains a trellis representation of the 17PP code based on the coding table 12 built in the 17PP coding unit 11, and holds it in the soft information memory 35 based on the obtained trellis representation of the 17PP code. The soft decision Viterbi decoding is performed using the soft information thus obtained, and the reproduced signal obtained as a result is output to the subsequent stage. This completes the playback process.

  As described above, according to the recording / reproducing apparatus 10 to which the present invention is applied, the PR-SISO decoding unit adopts the integrated trellis expression that integrates the NRZI encoding and the three trellis expressions corresponding to the PR12221 channel. The number of soft information supplied from 32 to the 17PP-SISO decoding unit 34 can be reduced. Therefore, the capacity of the soft information memory 35 built in the 17PP-SISO decoding unit 34 can be reduced. Therefore, the circuit scale of the decoding unit 31 that performs decoding processing including soft input / soft output decoding can be reduced as compared with the conventional one.

  In the present embodiment, three times of trellis expressions corresponding to NRZI coding and PR12221 channel are integrated. However, soft information is reduced by integrating two hours or more. You may make it do.

  In the present embodiment, the case where the PR communication path is the PR12221 channel has been described as an example. However, the present invention can also be applied to the case where the PR communication path is PR121, PR1221, and the like.

  Further, the present invention integrates several times of trellis representations corresponding to NRZI coding and PR12221 channel, but modulation code (in this embodiment, 17PP code), and NRZI coding and PR12221 channel. You may make it integrate for several time of the synthetic | combination trellis expression corresponding to.

  Furthermore, in the present embodiment, the playback process from the recording medium by the recording / playback apparatus has been described. However, the present invention is not limited to the case of performing the playback process, and the encoded signal is transmitted via the network. It can also be applied to decoding processing in a transmission system.

  By the way, the above-described series of processing can be executed by hardware or can be executed by software. When a series of processing is executed by software, a program constituting the software may execute various functions by installing a computer incorporated in dedicated hardware or various programs. For example, it is installed from a program recording medium in a general-purpose personal computer or the like.

  FIG. 6 is a block diagram illustrating a hardware configuration example of a computer that executes the above-described series of processing by a program.

  In this computer 100, a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, and a RAM (Random Access Memory) 103 are connected to each other by a bus 104.

  An input / output interface 105 is further connected to the bus 104. The input / output interface 105 includes an input unit 106 including a keyboard, a mouse, and a microphone, an output unit 107 including a display and a speaker, a storage unit 108 including a hard disk and nonvolatile memory, and a communication unit 109 including a network interface. A drive 110 for driving a removable medium 111 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory is connected.

  In the computer 100 configured as described above, for example, the CPU 101 loads the program stored in the storage unit 108 to the RAM 103 via the input / output interface 105 and the bus 104 and executes the program. A series of processing is performed.

  The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

  Further, in this specification, the system represents the entire apparatus constituted by a plurality of apparatuses.

  The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

It is a block diagram which shows the structural example of the recording / reproducing apparatus to which this invention is applied. It is a figure which shows the trellis expression for 1 time corresponding to PR12221 channel. It is a figure which shows the trellis expression for 3 time corresponding to PR12221 channel. FIG. 4 is a diagram illustrating an integrated trellis expression equivalent to the trellis expression of FIG. 3. It is a flowchart explaining a reproduction | regeneration process. And FIG. 11 is a block diagram illustrating a configuration example of a general-purpose computer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Recording / reproducing apparatus, 11 17PP decoding part, 12 Encoding table, 21 PR communication channel, 22 Recording / reproducing part, 23 Recording media, 24 Equalization processing part, 31 Decoding part, 32 PR-SISO decoding part, 33 Integration part, 34 17PP-SISO decoder, 35 Soft information memory

Claims (9)

Equalization means for equalizing a signal that has been modulated and encoded by a predetermined modulation code system in accordance with a predetermined PR (Partial Response) characteristic;
Based on the equalized signal, a trellis expression corresponding to the predetermined PR characteristic and representing a state transition table representing an encoding process at each time is developed along a time series, and based on the obtained trellis expression PR-SISO (Partial Response Soft-Input Soft-Output) decoding means for calculating soft information corresponding to each branch of the trellis expression by performing soft input soft output decoding,
Integration means for integrating the calculated soft information for a predetermined time;
Holding means for holding the integrated soft information;
Modulation decoding based on a trellis expression corresponding to the predetermined modulation code method, and demodulating an original signal before being modulated and encoded by the predetermined modulation code method, using the held integrated soft information And a demodulator. The demodulator according to claim 1, wherein the predetermined PR characteristic is a PR12221, PR1221, or PR121 channel. The demodulator according to claim 1, wherein the predetermined modulation and coding scheme is a 17PP (Parity Preserve / Prohibit Repeated Minimum Transition Runlength) code. The demodulator according to claim 3, wherein the integration unit integrates soft information corresponding to each branch of the trellis expression corresponding to the predetermined PR characteristic every three times. In a demodulation method of a demodulator that demodulates an original signal from a signal that has been modulated and encoded by a predetermined modulation code method,
According to the demodulator
Equalizes a signal that has been modulated and encoded by a predetermined modulation code method in accordance with a predetermined PR (Partial Response) characteristic,
Based on the equalized signal, a trellis expression corresponding to the predetermined PR characteristic and representing a state transition table representing an encoding process at each time is developed along a time series, and based on the obtained trellis expression Soft information corresponding to each branch of the trellis representation is calculated by performing soft input soft output decoding,
Integrate the calculated soft information for a predetermined time,
Holding the integrated soft information,
Based on the trellis representation corresponding to the predetermined modulation code scheme, the step of demodulating the original signal before being modulated and encoded by the predetermined modulation code scheme using the integrated soft information held therein Including demodulation methods. Computer
Equalization means for equalizing a signal that has been modulated and encoded by a predetermined modulation code system in accordance with a predetermined PR (Partial Response) characteristic;
Based on the equalized signal, a trellis expression corresponding to the predetermined PR characteristic and representing a state transition table representing an encoding process at each time is developed along a time series, and based on the obtained trellis expression PR-SISO (Partial Response Soft-Input Soft-Output) decoding means for calculating soft information corresponding to each branch of the trellis expression by performing soft input soft output decoding,
Integration means for integrating the calculated soft information for a predetermined time;
Holding means for holding the integrated soft information;
Modulation decoding based on a trellis expression corresponding to the predetermined modulation code method, and demodulating an original signal before being modulated and encoded by the predetermined modulation code method, using the held integrated soft information Program to function as a means. Encoding means for generating an encoded signal by modulating and encoding an input signal by a predetermined modulation encoding method;
Recording means for recording the encoded signal on a recording medium;
Equalization means for reading the signal recorded on the recording medium and equalizing the read signal corresponding to a predetermined PR (Partial Response) characteristic;
Based on the equalized signal, a trellis expression corresponding to the predetermined PR characteristic and representing a state transition table representing an encoding process at each time is developed along a time series, and based on the obtained trellis expression PR-SISO (Partial Response Soft-Input Soft-Output) decoding means for calculating soft information corresponding to each branch of the trellis expression by performing soft input soft output decoding,
Integration means for integrating the calculated soft information for a predetermined time;
Holding means for holding the integrated soft information;
Modulation decoding based on a trellis expression corresponding to the predetermined modulation code method, and demodulating an original signal before being modulated and encoded by the predetermined modulation code method, using the held integrated soft information And a recording / reproducing apparatus. In a recording / reproducing method of a recording / reproducing apparatus for recording and reproducing an input signal on a recording medium,
According to the recording / reproducing apparatus,
An input signal is modulated and encoded by a predetermined modulation code method to generate an encoded signal,
Recording the encoded signal on a recording medium;
Read the signal recorded on the recording medium,
The read signal is equalized corresponding to a predetermined PR (Partial Response) characteristic,
Based on the equalized signal, a trellis expression corresponding to the predetermined PR characteristic and representing a state transition table representing an encoding process at each time is developed along a time series, and based on the obtained trellis expression Soft information corresponding to each branch of the trellis representation is calculated by performing soft input soft output decoding,
Integrate the calculated soft information for a predetermined time,
Holding the integrated soft information,
Based on the trellis representation corresponding to the predetermined modulation code scheme, the step of demodulating the original signal before being modulated and encoded by the predetermined modulation code scheme using the integrated soft information held therein Including recording and playback methods. On the computer,
Encoding means for generating an encoded signal by modulating and encoding an input signal by a predetermined modulation encoding method;
Recording means for recording the encoded signal on a recording medium;
Equalization means for reading the signal recorded on the recording medium and equalizing the read signal corresponding to a predetermined PR (Partial Response) characteristic;
Based on the equalized signal, a trellis expression corresponding to the predetermined PR characteristic and representing a state transition table representing an encoding process at each time is developed along a time series, and based on the obtained trellis expression PR-SISO (Partial Response Soft-Input Soft-Output) decoding means for calculating soft information corresponding to each branch of the trellis expression by performing soft input soft output decoding,
Integration means for integrating the calculated soft information for a predetermined time;
Holding means for holding the integrated soft information;
Modulation decoding based on a trellis expression corresponding to the predetermined modulation code method, and demodulating an original signal before being modulated and encoded by the predetermined modulation code method, using the held integrated soft information Program to function as a means.

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