JP4639827B2 - Audio output device, synchronization adjustment system, and synchronization adjustment method - Google Patents

Description

  The present invention relates to an audio output device, a synchronization adjustment system, and a synchronization adjustment method.

  Patent Document 1 discloses a time difference measuring apparatus for a television video signal and an audio signal. The time difference measuring apparatus disclosed in Patent Document 1 uses a television video signal and an audio signal generated at the same time when they are transmitted or processed via different transmission paths or signal processing circuits and then used for monitoring. It measures the arrival time difference between the video signal and the audio signal.

  The time difference measuring apparatus disclosed in Patent Document 1 includes means for obtaining television video and audio based on a television video signal and an audio signal, respectively, in order to measure the arrival time difference between the video signal and the audio signal. An optical-electrical converter for converting a temporal luminance change in a part of the screen of a television image to an electric signal of a corresponding level, and an electric signal obtained by the optical-electrical converter A first waveform shaping circuit for shaping the signal into a binary pulse signal, a first one-pulse generation circuit for generating one pulse from the output of the first waveform shaping circuit, and the obtained television sound. A microphone that converts the electrical signal corresponding to the level of the sound, a differentiation circuit that differentiates the electrical signal obtained by the microphone, and a second waveform that shapes the output of the differentiation circuit into a binary pulse signal Circuit, a second one-pulse generating circuit that generates one pulse from the output of the second waveform shaping circuit, and a gate-on at the output of the first one-pulse generating circuit. A gate circuit that gates off at the output, a counter circuit that measures a period in which the gate circuit is gate-on by counting the number of clock pulses included in the period, and a time display that displays a count result by the counter circuit A vessel.

Japanese Patent Laid-Open No. 10-285483 (claims, detailed description of the invention, etc.)

  Incidentally, in recent years, digital flat displays typified by plasma display devices have been developed and are beginning to spread. Among them, the plasma display device has an advantage that a large screen can be easily commercialized as compared with a general liquid crystal display device using a TFT (Thin Film Transistor). The plasma display device may be used as a home theater system in combination with, for example, an audio amplifier device because of its large screen and high image quality display capability.

  However, when this digital flat display device and an audio amplifier device are used in combination, the following problems arise.

  For example, taking a plasma display device as an example, the display driver applies a voltage to the address electrode and the display electrode of the plasma light emitting display unit, and this voltage generates a plasma discharge in a desired discharge cell. The phosphor provided in the discharge cell is caused to emit light by the accompanying ultraviolet rays. In addition, the plasma display device converts signals input to the video A / D conversion unit, signal processing unit, display driver, and the like in order to convert the moving image input thereto into control signals applied to the address electrodes and display electrodes of the plasma light emitting display unit. It has a processing system circuit.

  Therefore, in the plasma display device, a large delay time is generated after an analog video signal is input until a display screen based on the signal is displayed. In the plasma display apparatus, a particularly large delay time may occur. The delay of the display screen can be tens to hundreds of milliseconds.

  As described above, the digital flat panel display device has a large delay from when a signal is input thereto until the display screen based on the signal is displayed. As a result, when these devices and an audio amplifier device are used in combination, audio is output from the audio amplifier device before the display device displays an image. That is, sound is output ahead of the video. For example, in a scene where two people are fighting, after a sound is heard, a screen on which people are beaten is displayed.

  When the sound lags behind the video, for example, if one imagines that there is a lightning in the distance, the person feels that the video scene is being developed far away, and is unlikely to cause a sense of incongruity. However, if the sound precedes the video, it cannot be in the real world, so even if the degree of advance is very little time, a sense of incongruity is likely to occur.

  Such a situation can occur more or less in other types of display devices.

  Then, in order to adjust the synchronization between the image of the plasma display device and the sound output from the audio amplifier device so as not to cause such a sense of incongruity, the time difference measuring device as described in Patent Document 1 is used. Must be used to measure the amount of shift between video and audio. Such a time difference measuring device is used only for measuring the value of the amount of deviation between video and audio, and is not something that can be purchased and used by ordinary people.

  The present invention relates to an audio output device, a synchronization adjustment system, and a synchronization adjustment method capable of easily adjusting the synchronization between an image of a display device such as a plasma display device and an output sound of an audio output device such as an audio amplifier device. The purpose is to obtain.

In order to achieve the above object, the audio output device of the present invention outputs a first audio signal to a display device having a first delay circuit that delays the audio signal for a predetermined time in order to synchronize with the video signal. Output means for delaying the first audio signal by a first delay circuit for a predetermined time, and input means for inputting a second audio signal synchronized with the video signal from the display device, and delaying the first audio signal A second delay circuit for outputting a delayed first audio signal for output to a speaker separate from the display device, a first audio signal delayed by the second delay circuit, and a second Determining means for comparing the two audio signals and determining whether the delay time of the first audio signal delayed by the second delay circuit is equal to the delay time of the second audio signal; If the means determines that they are not equal, the second It has a adjusting means for adjusting the delay amount of the first audio signal by extending circuit.

In addition to the above-described invention, in the audio output device of another invention, the determination unit determines the delay amount from the time difference between the first audio signal and the second audio signal delayed by the second delay circuit. I am doing so.

Also, the audio output device of another invention, in addition to the above-mentioned invention, while compared with the first audio signal delayed by the second audio signal and the second delay circuit by determining means, adjusting means The delay amount of the first audio signal delayed by the second delay circuit is changed, and the delay amount when the phases of these audio signals coincide with each other is obtained.

In addition to the above-described invention, in the audio output device of another invention, the output means outputs a predetermined audio signal output from an external audio reproduction device to the display device .

In addition to the above-described invention, in the audio output device of another invention, the input means is connected to the headphone output terminal.

In addition to the above-described invention, the audio output device of another invention has the input means connected to the line output terminal.

In addition to the above-described invention, in the audio output device of another invention, the first audio signal and the second audio signal are a sine wave signal or a rectangular wave signal whose frequency changes at a cycle of 100 ms or more.

In addition to the above-described invention, the audio output device of another invention has at least two different frequency signals for the first audio signal and the second audio signal, and the signal of any one of the frequencies is It changes with a period of 100 ms or more.

In addition to the above-described invention, in the audio output device of another invention, the first audio signal and the second audio signal have a frequency in the range of 10 kHz to 100 Hz.

Also, the audio output device of another invention, in addition to the above invention further includes a generating means for generating a first audio signal, output means, outputs the first audio signal generated by the generation means To do.

In addition to the above-described invention, the audio output device according to another aspect of the invention may be configured such that when the output unit is instructed to adjust the delay amount by the adjustment unit, the first audio signal generated by the generation unit In other cases, a predetermined audio signal output from an external audio reproduction device is input and output.

The synchronous adjustment system of the present invention, each sound output apparatus described above, is connected to the audio output device, and the audio signal reproducing apparatus for reproducing and outputting a least audio signals, it is connected via an audio output device, movies And a display device that inputs and reproduces an image signal and an audio signal synchronized with the image signal.

In addition, the synchronization adjustment method of the present invention is a synchronization adjustment method executed by the audio output device, and is the first for a display device having a first delay circuit that delays the audio signal for a predetermined time in order to synchronize with the video signal. An output step of outputting one audio signal, an input step of delaying the first audio signal by a first delay circuit for a predetermined time and inputting a second audio signal synchronized with the video signal from the display device; A second delay step of delaying one audio signal by a second delay circuit and outputting a delayed first audio signal for output to a speaker separate from the display device; and a second delay The first audio signal delayed by the processing of the step is compared with the second audio signal, the delay time of the first audio signal delayed by the processing of the second delay step and the delay of the second audio signal Whether time is equal A determination step of determining, if it is not equal the determination step comprises an adjusting step of adjusting the delay amount of the first audio signal by the processing of the second delay step.

  The present invention relates to an audio output device, a synchronization adjustment system, and a synchronization adjustment method capable of easily adjusting the synchronization between an image of a display device such as a plasma display device and an output sound of an audio output device such as an audio amplifier device. Can be provided.

  Hereinafter, an audio output device, a synchronization adjustment system, and a synchronization adjustment method according to embodiments of the present invention will be described with reference to the drawings. The audio output device will be described by taking an audio amplifier device as an example. The synchronization adjustment method will be described as the operation of the synchronization adjustment system.

Embodiment.
FIG. 1 is a diagram showing a synchronization adjustment system according to an embodiment of the present invention. The synchronization adjustment system includes a disc 1 as a recording medium on which video and audio are recorded, a disc reproducing device 2 as an audio signal reproducing device for reproducing the disc 1, a plasma display device 3 as a display device, and an audio output. An audio amplifier device 4 as a device and a speaker 5 are provided.

  FIG. 2 is a block diagram showing the configuration of the plasma display device 3 in FIG. The plasma display device 3 that is the object of synchronization adjustment includes an analog video input terminal 3a, a video A / D (Analog to Digital) conversion unit 3c, a signal processing unit 3d, a display driver 3e, and a plasma light emitting display unit 3f. Have. In addition, the plasma display device 3 includes an analog audio input terminal 3b, a delay circuit 3g, an amplifier circuit 3h, a built-in speaker 3i, and a headphone connection terminal 3j.

  The plasma light emitting display 3f has a plurality of discharge cells not shown. The plurality of discharge cells are arranged in a two-dimensional matrix. The discharge cell is formed for each color element of the display pixel (for example, each color in a combination of colors such as red, green, and blue).

  The discharge cell has a structure in which a gas is sealed in a cavity between an address electrode and a display electrode. A phosphor that fluoresces in the display color of each discharge cell is disposed in the cavity. When a high voltage is applied between the address electrode and the display electrode, the sealed gas emits plasma. The phosphors provided in the discharge cells emit the respective display colors with ultraviolet rays generated by the plasma emission.

  An analog video signal is input to the analog video input terminal 3 a of the plasma display device 3. The analog video signal includes, for example, an analog video signal in an NTSC (National Television System Committee) method or a PAL (Phase Alternating Line) method, or an analog video signal in a format for video input / output of digital broadcasting. An analog video input terminal to which an analog video signal in a format for video input / output of digital broadcasting is input is generally called a D1 terminal or the like.

  These analog video signals have a video signal related to one display screen every predetermined period such as 1/30 second. In the analog video signal, the video signal of one display screen is configured in units of waveform components corresponding to the luminance distribution for each horizontal scanning line when the display screen is displayed on a beam scanning display device using a cathode ray tube. The One display screen is composed of a predetermined number of waveform components for each horizontal scanning line such as 480 or 525.

  The analog video input terminal 3a of the plasma display device 3 is connected to the video A / D converter 3c. The video A / D converter 3c samples the analog video signal input to the analog video input terminal 3a, converts it to a digital signal, and outputs it. The signal processing unit 3d generates two-dimensional image data for each display screen in the analog video signal based on the sampling data from the video A / D conversion unit 3c. The display driver 3e applies a voltage according to the two-dimensional image data generated by the signal processing unit 3d to the address electrode and the display electrode of the plasma light emitting display unit 3f. When the potential difference between an address electrode and a display electrode becomes a high voltage, the discharge cells corresponding to the address electrode and the display electrode are plasma-discharged and fluoresce in a predetermined display color.

  Thus, based on the waveform component of the display screen in the analog video signal input to the analog video input terminal 3a, the plasma light emission display unit 3f displays the display screen. When the analog video signal is switched to the waveform component of the next display screen, the display screen displayed by the plasma light emission display unit 3f is switched accordingly. Thereby, the plasma display apparatus 3 can display the moving image in which a display screen switches with a predetermined period based on an analog video signal.

  An analog audio signal is input to the analog audio input terminal 3 b of the plasma display device 3. The analog audio signal is a signal having a predetermined audio waveform component. The analog audio signal is a signal that can output a predetermined audio signaled as an analog audio signal from the speaker 3i by driving the speaker 3i based on the analog audio signal.

  The analog audio input terminal 3b of the plasma display device 3 is connected to the delay circuit 3g. The delay circuit 3g converts an analog audio signal input from the analog audio input terminal 3b into a predetermined delay amount (a delay corresponding to a time from when an analog video signal is input to when a display screen based on the signal is displayed). Output by delay). As a result, the video signal and the audio signal are synchronized. Note that such a delay circuit 3g is an optimum delay according to the characteristics of the signal processing unit 3d, the plasma driver 3e, and the plasma light emitting display unit 3f of each manufacturer at the design stage of the plasma display device 3. The amount is set. In the present invention, synchronization adjustment for synchronizing video and audio is performed by measuring the delay amount of the delay circuit 3g.

  The output of the delay circuit 3g is connected to the amplifier circuit 3h. The amplifier circuit 3h amplifies the analog audio signal output from the delay circuit 3g. The amplifier circuit 3h outputs the amplified analog audio signal to the built-in speaker 3i and the headphone connection terminal 3j. The built-in speaker 3i is vibrated according to the waveform component of the amplified analog audio signal. The plasma display device 3 outputs a sound according to the analog sound signal input to the analog sound input terminal 3a. The headphone connection terminal 3j is connected to a headphone (not shown) in a normal state, and is connected to an adjustment audio input terminal 4r of the audio amplifier device 4 to be described later when performing synchronization adjustment.

  FIG. 3 is a block diagram showing the configuration of the audio amplifier device 4 in FIG. The audio amplifier device 4 has an analog video input terminal 4a and an analog video output terminal 4q. The audio amplifier device 4 includes an analog audio input terminal 4b, a test data generation unit 4c as a generation unit, an audio input switching circuit 4d, an input unit 4e, an audio A / D conversion unit 4f, and a calculation unit. A control circuit 4g as a part, a delay data memory 4h, a digital delay circuit 4i as a delay means, a coincidence detection circuit 4j as a part of a calculation means, and a voice D / A (Digital to Analog) converter 4k An audio output stop circuit 4m, an audio A / D converter 4n, an amplifier circuit 4p, an adjustment audio input terminal 4r as input means, an analog audio output terminal 4s, and an analog audio output terminal as output means 4t.

  The analog video input terminal 4a of the audio amplifier device 4 is connected to the analog video output terminal 4q. The analog video output terminal 4q outputs an analog video signal input to the analog video input terminal 4a. In practice, a plurality of analog video input terminals 4a are provided together with an analog audio input terminal 4b, which will be described later, and a video signal and an audio signal from an arbitrary terminal are selected by a selector, and the analog video output terminal 4q and the analog audio input terminal are selected. Output from output terminals 4s and 4t.

  The test data generator 4c of the audio amplifier device 4 generates and outputs test data (described later) that is a predetermined audio signal when adjusting the synchronization. The audio input switching circuit 4d selects the output of the test data generating unit 4c when adjusting the synchronization, and selects the output from the analog audio input terminal 4b in the normal case. The input unit 4e outputs input data such as numerical values according to a user input operation. The audio A / D converter 4f samples the analog audio signal output from the audio input switching circuit 4d, converts it to a digital signal, and outputs it. The digital delay circuit 4i delays the digital value input thereto by a time corresponding to the value of the delay data stored in the delay data memory 4h, and outputs it. The delay data memory 4h is constituted by, for example, a nonvolatile semiconductor memory, and holds delay data for determining the delay amount of the digital delay circuit 4i. Thus, the audio D / A converter 4k outputs an analog audio signal obtained by delaying the analog audio signal input to the analog audio input terminal 4b by a time corresponding to the value of the delay data stored in the delay data memory 4h. Is done.

  In addition, according to the investigation test by the inventors, it has been found that when a voice precedes for 200 milliseconds or more, even a normal person is concerned about the precedence of the sound. For this reason, the delay data memory 4h and the digital delay circuit 4i may be configured to output a digital value with a delay of, for example, 100 milliseconds or more, preferably 200 milliseconds or more.

  The control circuit 4g is constituted by, for example, a CPU (Central Processing Unit) or the like, and controls each unit of the apparatus. The coincidence detection circuit 4j compares the digital audio signal output from the audio A / D conversion unit 4n with the digital audio signal output from the digital delay circuit 4i, and determines whether or not their phases match. To do. The audio D / A converter 4k converts the digital audio signal output from the digital delay circuit 4i into an analog audio signal and outputs the analog audio signal. The audio output stop circuit 4m stops the output of the analog audio signal to the amplifier circuit 4p when performing the synchronization adjustment. The amplifier circuit 4p amplifies and outputs the output of the audio output stop circuit 4m with a predetermined gain. As shown in FIG. 1, a speaker 5 is connected to the analog audio output terminal 4s. The analog audio output terminal 4t is connected to the analog audio input terminal 3b shown in FIG. The speaker 5 outputs a predetermined sound signaled as an analog sound signal.

  The synchronization adjustment system according to the embodiment of the present invention is for adjusting the sound and synchronization of the plasma display device 3 having the above configuration and functions. The synchronization adjustment system according to the embodiment of the present invention includes a moving image displayed by the plasma display device 3 based on an analog video signal, and a sound output from a speaker 5 connected to the audio amplifier device 4 based on an analog audio signal. It is for adjusting the synchronization.

  The disc 1 is an optical disc that can be read by the disc playback device 2. Optical disks include DVD-ROM, DVD-RAM, DVD-R, DVD + R, CD, and CD-R. On the disc 1, video and audio including moving images are recorded.

  Next, an adjustment method for adjusting the synchronization between the plasma display device 3 and the audio amplifier device 4 using the audio synchronization system shown in FIG. 1 will be described.

  The user first connects the disc playback device 2, the plasma display device 3, and the audio amplifier device 4 using the connection cables 6 to 9. Further, the headphone connection terminal 3j of the plasma display device 3 and the adjustment audio input terminal 4r of the audio amplifier device are connected by the connection cable 10.

  After the above preparation is completed, the user operates the input unit 4e to instruct to start the synchronization adjustment process. As a result, the processing of the flowchart shown in FIG. 4 is started and the following steps are executed.

  Step S10: The control circuit 4g controls the audio output stop circuit 4m to stop the output of the audio signal to the speaker 5. As a result, it is possible to prevent a special audio signal generated during the synchronization adjustment from being reproduced by the speaker 5. The plasma display device 3 also has a built-in speaker 3i. However, since the connection cable 10 is connected to the headphone connection terminal 3j, no sound is emitted from the built-in speaker 3i.

  Step S11: The control circuit 4g switches the connection of the audio input switching circuit 4d from the analog audio input terminal 4b to the test data generating unit 4c side. As a result, the output of the test data generation unit 4c is selected and supplied to the circuits after the audio A / D conversion unit 4f.

  Step S12: The control circuit 4g controls the test data generator 4c to start generating test data. FIG. 5 is a diagram illustrating an example of test data (analog audio signal) output from the test data generation unit 4c. In this example, a rectangular wave repeated at a period T is used as test data.

  Step S13: The control circuit 4g assigns “0” as an initial value to the variable d for storing the delay amount.

  Step S14: The control circuit 4g sets the delay amount of the digital delay circuit 4i to d. That is, the control circuit 4g stores the value stored in the variable d in the delay data memory 4h. As a result, since the digital delay circuit 4i sets the delay amount based on the value stored in the delay data memory 4h, the delay amount corresponding to the value stored in the variable d is set.

  At this time, since the voice input switching circuit 4d selects the test data output from the test data generator 4c, the test data output from the test data generator 4c is sampled in the voice A / D converter 4f. And converted into a digital signal. The digital delay circuit 4i delays the digital signal output from the audio A / D converter 4f according to the delay data stored in the delay data memory 4h and outputs the delayed signal. The output of the digital delay circuit 4i is supplied to the coincidence detection circuit 4j.

  The test data output from the audio input switching circuit 4d is supplied to the analog audio input terminal 3b of the plasma display device 3 through the analog audio output terminal 4t. The test data input from the analog audio input terminal 3b is delayed by the delay circuit 3g, then amplified by the amplifier circuit 3h, and supplied to the adjustment audio input terminal 4r of the audio amplifier device 4 via the headphone connection terminal 3j. Is done. The test data input from the adjustment audio input terminal 4r is sampled and converted into a digital signal by the audio A / D converter 4n, and then supplied to the coincidence detection circuit 4j. The operation of the coincidence detection circuit 4j will be described later.

  Step S15: The control circuit 4g refers to the output of the coincidence detection circuit 4j, and determines whether or not the signal input from the audio A / D conversion unit 4n matches the signal output from the digital delay circuit 4i. If it matches, the process proceeds to step S17, otherwise the process proceeds to step S16.

  That is, as shown in FIG. 5, the coincidence detection circuit 4j calculates the exclusive OR of the output signal of the audio A / D conversion unit 4n and the output signal of the digital delay circuit 4i, and outputs the result as the coincidence detection circuit 4j output signal. Output. As a result, when the delay time of the output signal of the audio A / D converter 4n and the output signal of the digital delay circuit 4i are equal, the output is “0”, but when the delay time is shifted, the phase is shifted. A rectangular wave having a width corresponding to the deviation is output.

  Step S16: The control circuit 4g increments the value of the variable d by 1, returns to step S14, and repeats the same processing.

  Through the processing in steps S14 to S16 described above, the phase of the output signal of the audio A / D converter 4n and the output signal of the digital delay circuit 4i are compared. If they are not equal, the delay of the digital delay circuit 4i The amount is incremented by 1 which is a unit delay amount, and coincidence detection is repeated. And when these phases become equal, it progresses to step S17. Through a series of these processes, the delay amount of the digital delay circuit 4 i is adjusted to be substantially equal to the delay amount of the delay circuit 3 g of the plasma display device 3.

  Step S17: The control circuit 4g fixes the delay amount of the digital delay circuit 4i to the value d. That is, the control circuit 4g writes the value of the variable d in the delay data memory 4h.

  Step S18: The control circuit 4g switches the connection of the audio input switching circuit 4d from the test data generating unit 4c to the analog audio input terminal 4b side. As a result, for example, an analog audio signal output from the disk playback device 2 is supplied to the audio A / D converter 4f.

  Step S19: The control circuit 4g controls the audio output stop circuit 4m to release the audio output stop state. As a result, the analog audio signal output from the audio D / A converter 4k is supplied to the amplifier circuit 4p.

  According to the above processing, when a synchronization adjustment instruction is given from the input unit 4e, the delay amount of the digital delay circuit 4i is adjusted to be substantially the same as the delay amount of the delay circuit 3g of the plasma display device 3. Therefore, even when an analog audio signal is output from the speaker 5, it is possible to achieve synchronization with the video displayed on the plasma display device 3. As a result, it is possible to enjoy video and audio with no sense of incongruity. Moreover, the user who purchased the plasma display device 3 and the audio amplifier device 4 can easily perform the synchronization adjustment without purchasing a special dedicated device at home.

  In the above-described embodiment, the analog video signal is input to the plasma display device 3 via the audio amplifier device 4. However, for example, as shown in FIG. It is also possible to supply the video signal directly to the plasma display device 3. In this example, the disk reproducing device 2 and the plasma display device 3 are directly connected by a connection cable 6 so that an analog video signal is transmitted between them. That is, in the above-described embodiment, since the video and audio are synchronized using only the analog audio signal, the analog video signal does not need to be input to the audio amplifier device 4. Note that it is only necessary to be able to supply an audio signal. Therefore, for example, a cassette tape playback device or a DAT (Digital Audio Tape) playback device may be used instead of the disk playback device 2.

  Further, in the above-described embodiment, the rectangular wave signal shown in FIG. 5 is used as the test data. However, in such a rectangular wave signal, when the phase is shifted by one cycle or more of the rectangular wave, the delay amount Is difficult to detect. Therefore, for example, as in the first test data shown in FIG. 7, a synchronization interval with a wide rectangular wave is periodically provided, and by detecting this portion, it is determined whether or not there is a shift of one cycle or more. If the phase is shifted by more than one cycle, the delay amount is detected in detail in the phase adjustment section composed of a rectangular wave having a normal width after adjusting the phase using the synchronization section. Good.

  Further, as shown in the second test data in FIG. 7, it is possible to detect the delay amount using a signal having a period longer than the expected delay amount. That is, when the maximum expected delay amount is T, a signal having a longer period than T can be used to cope with a case where the delay amount is large. Specifically, since the delay amount is often within 200 ms, T can be set to about 200 ms.

  In the above-described embodiment, a rectangular wave is used as the test data. However, for example, an FM (Frequency Modulation) modulated signal can be used as in the third test data in FIG. is there. In this example, a signal having a high frequency and a signal having a low frequency are mixed, and a signal having a high frequency is determined to be in a high state as shown in the third test data detection value, and a signal having a low frequency is low. It is judged as a state. Therefore, the delay amount can be detected by comparing the high or low state of the detection value. By using the FM modulated signal in this way, for example, when the low frequency characteristics of the amplifier circuit 3h built in the plasma display device 3 are not sufficient (for example, when the low frequency limit is about 40 to 50 Hz). Even in such a case, by using a signal having a somewhat high frequency (for example, 100 to 10 kHz) as a carrier wave, the delay amount can be accurately measured without being influenced by the low frequency characteristics of the amplifier circuit 3h. More preferably, the frequency may be determined according to a desired resolution. For example, when the resolution is set to about 1 ms, it may be set to a frequency (10 kHz) with a period of about 0.1 ms.

  In the above-described embodiment, the input to the audio amplifier device 4 is an analog signal, but a digital signal may be input. The input to the plasma display device 3 may also be a digital signal. In short, as long as the time difference between the audio signal input to the plasma display device 3 and the output audio signal can be obtained, the signal may be expressed in any format.

  Further, in the above-described embodiment, the delay amount is detected using the analog audio signal from the headphone connection terminal 3j of the plasma display device 3. However, even if the delay amount is other than the headphone connection terminal 3j, the delay circuit 3g is used. Thus, any signal that is output can be used. That is, any signal (for example, a signal from a line output terminal or the like) can be used as long as the audio signal is adjusted so as to be synchronized with the video.

  In the above-described embodiment, when the input unit 4e is operated to instruct synchronization adjustment, the above-described processing (the processing in FIG. 4) is executed. When the connection cable 10 is connected to 4r, when a predetermined time has passed since the connection, or when an audio signal is detected after being connected, the above-described processing may be started.

  The present invention can be used in a home theater system or the like that uses a plasma display device and an audio amplifier device to synchronize their moving images and sound.

It is a block diagram which shows the structural example of the synchronous adjustment system which concerns on embodiment of this invention. It is a block diagram which shows the structural example of the plasma display apparatus which comprises the synchronous adjustment system which concerns on embodiment shown in FIG. It is a block diagram which shows the structural example of the audio amplifier apparatus which comprises the synchronous adjustment system which concerns on embodiment shown in FIG. It is a flowchart for demonstrating the flow of a process at the time of performing synchronous adjustment in the synchronous adjustment system which concerns on embodiment shown in FIG. It is a timing chart which shows the signal of each part of the synchronous adjustment system which concerns on embodiment shown in FIG. It is a figure which shows the other example of a connection of the synchronous adjustment system of this invention. It is a figure which shows another example of the test data used in the synchronous adjustment system of this invention.

Explanation of symbols

1 disc 2 disc playback device (audio signal playback device)
3 Plasma display device (display device)
4 Audio amplifier device (audio output device)
4c Test data generation part (generation means)
4g Control circuit (part of calculation means)
4i Digital delay circuit (delay means)
4j coincidence detection circuit (part of calculation means)
4r input terminal (input means)
4t output terminal (output means)
4u delay amount detection circuit (part of calculation means)

Claims (13)

Output means for outputting a first audio signal to a display device having a first delay circuit for delaying the audio signal for a predetermined time in order to synchronize with the video signal;
Input means for delaying the first audio signal by the first delay circuit for a predetermined time and inputting a second audio signal synchronized with the video signal from the display device;
A second delay circuit for outputting the delayed first audio signal for delaying the first audio signal and outputting it to a speaker separate from the display device ;
The first audio signal delayed by the second delay circuit is compared with the second audio signal, and the delay time of the first audio signal delayed by the second delay circuit is compared with the first audio signal. Determining means for determining whether or not the delay times of the two audio signals are equal;
An adjusting means for adjusting a delay amount of the first audio signal by the second delay circuit when the determining means determines that they are not equal;
An audio output device comprising:   2. The audio output device according to claim 1, wherein the determination unit determines a delay amount from a time difference between the first audio signal delayed by the second delay circuit and the second audio signal.   The adjustment means compares the first audio signal delayed by the second delay circuit with the first audio signal delayed by the second delay circuit while comparing the second audio signal and the first audio signal delayed by the second delay circuit. 2. The audio output device according to claim 1, wherein the delay amount of the audio signal is changed, and the delay amount is obtained when the phases of the audio signals coincide with each other.   2. The audio output device according to claim 1, wherein the output means outputs a predetermined audio signal output from an external audio reproduction device to the display device.   2. The audio output device according to claim 1, wherein the input means is connected to a headphone output terminal.   2. The audio output device according to claim 1, wherein the input means is connected to a line output terminal.   2. The audio output device according to claim 1, wherein the first audio signal and the second audio signal are a sine wave signal or a rectangular wave signal whose frequency changes at a cycle of 100 ms or more.   The first audio signal and the second audio signal have signals of at least two different frequencies, and the signal of any one of the frequencies changes in a cycle of 100 ms or more. Audio output device.   9. The audio output device according to claim 7, wherein the first audio signal and the second audio signal have a frequency in a range of 10 kHz to 100 Hz. Further comprising generating means for generating the first audio signal;
2. The audio output apparatus according to claim 1, wherein the output unit outputs the first audio signal generated by the generation unit.   The output means outputs the first audio signal generated by the generating means when instructed to adjust the delay amount by the adjusting means, and in other cases, an external audio reproduction device The audio output apparatus according to claim 10, wherein a predetermined audio signal output from the audio signal is input and output. The audio output device according to any one of claims 1 to 6,
An audio signal reproduction device connected to the audio output device and reproducing and outputting at least an audio signal;
A display device that is connected via the audio output device and receives and reproduces a video signal and an audio signal synchronized with the video signal;
A synchronization adjustment system comprising: A synchronization adjustment method executed by the audio output device,
An output step of outputting the first audio signal to a display device having a first delay circuit that delays the audio signal for a predetermined time in order to synchronize with the video signal;
An input step of delaying the first audio signal by the first delay circuit for a predetermined time and inputting a second audio signal synchronized with the video signal from the display device;
A second delay step of delaying the first audio signal by a second delay circuit and outputting the delayed first audio signal for output to a speaker separate from the display device ;
The delay time of the first audio signal delayed by the processing of the second delay step by comparing the first audio signal delayed by the processing of the second delay step with the second audio signal And a determination step for determining whether or not the delay time of the second audio signal is equal;
An adjustment step of adjusting a delay amount of the first audio signal by the processing of the second delay step when it is determined that they are not equal by the determination step;
A method for adjusting synchronization, comprising:

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