JPH02131700A - Television receiver - Google Patents

Abstract

PURPOSE:To check a drive speaker and its sound volume and at a glance by displaying which speaker is outputting a test tone at present on a CRT by varying display mode in adjusting the sound volume of each speaker. CONSTITUTION:When the test mode switch of an operation section 12 is operated, a 3rd changeover switch 13 is switched to connect an input terminal of a surround decoder 3 to a test tone circuit 11. Thus, speakers are switched for 1.5sec each and driven. On the other hand, a microcomputer 14 discriminates from which speaker a test tone is outputted at present and supplies a color conversion control signal to a color conversion control circuit 15 based on the result of discrimination to control a character display circuit 16 by a color conversion signal outputted from the color conversion control circuit 15. Thus, the user can recognize which speaker is driven at present and operates the sound volume adjustment key of the operation section 12.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a television receiver incorporating a surround circuit.

BACKGROUND OF THE INVENTION In recent years, an increasing number of television receivers are equipped with various surround circuits. Among these, JP-A-54-6
The Dolby Surround System (trademark of Dolby Laboratories Licensing Corporation) disclosed in Publication No. 2801 (HO4R5/00) can be used as a theater in ordinary homes by playing back VTR software and video disc software recorded in the Dolby Surround format. This allows you to enjoy stereo sound with almost the same sense of realism.

However, in the Dolby surround system,
In principle, it was impossible to obtain the same surround effect as in a theater.

Therefore, as an expansion system for the above-mentioned Dolby Surround, Japanese Patent Laid-Open No. 61-251400 (H04S3/02
) is a ProLogic surround system (trademark of Dolby Laboratories Licensing Corporation) that has a built-in directional enhancement circuit. This Pro Logic surround system is different from the Dolby surround system, which reproduces the difference signal component between the left and right audio signals through the rear speakers to create a sense of presence, but by adding processing that further clarifies the directionality of the sound, it improves localization and creates a sense of presence. It is intended to improve Reproduction is performed by speakers for the L channel, R channel, and center channel (C) installed at the front, and a pair of speakers for the surround channel (S) installed at the rear.

As shown in FIG. 7, the system includes left and right input terminals (.1) and (2) to which left and right stereo signals L' and R° encoded by the Dolby surround system are applied, and left and right input terminals (. A first adding circuit (3) adds the left and right stereo signals L′ and R′ to create a sum signal C′ (=L′+R′), and subtracts the left and right stereo signals L′ and R′ to create a difference signal S′(=L′). − R') to create a subtraction circuit (
4), and II and second detection circuits (5) and (6) that detect the levels of the left and right stereo signals L° and R', respectively.
), third and fourth detection circuits (7) and (8) that detect the levels of the sum and difference signals C' and S', respectively;
first to level ratio detection circuits (9) for detecting the level ratio of the output signals of the first and second detection circuits (5) and (6); and the third and fourth detection circuits (7) and (8). ) A second level ratio detection circuit (10) that detects the level ratio of the output signals of
and the first and second level ratio detection circuits (9) and (1
VCA (t pressure control amplifier) (1) that controls the levels of the left and right stereo signals L° and R° according to the output signal of
l), the left and right stereo signals and VCA (11)
a second addition circuit (12) that selects and adds the output signals of the left and right stereo output signals L and R, and generates the left and right stereo output signals L and R, the center output signal C, and the surround output signal S; The center mode control circuit (13) switches the signal C according to the mode, and the passive decoder (14) performs signal processing such as delay and noise removal on the surround output signal S.

(c) Problems to be Solved by the Invention By the way, the Pro Logic surround system has a test mode function that allows the user to easily set the volume balance (sound field) of the five speakers at the listening position. There is. This test mode impairment is 500
H2 noise is played back for 1 to 2 seconds from each of the speakers in turn, and the user adjusts the volume balance of each speaker during that time.

However, in the test mode of the conventional Pro Logic surround decoder, there was no means to clearly display which speakers were currently being driven at what volume, making it difficult for the user to adjust the volume.

The present invention has been made in view of the above points, and provides a television receiver that can extremely easily adjust the volume balance of each speaker in a test mode.

(2) Means for Solving the Problems The present invention includes means for displaying the volume of each channel on the television screen, as well as displaying which channel's speaker the test tone is currently being applied to.

(E) Operation In the test mode, the present invention displays the speaker to which the test tone is currently applied on the television screen in conjunction with switching the speaker to which the test tone is applied at predetermined intervals.

(f) Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram of the device of this embodiment, and (1)
(2) is a 4-channel audio signal, (right channel (R
), left channel (L), center channel (C),
Surround channel (S)) is a 2-channel audio signal (S) encoded using the Dolby surround method.
Input terminal for inputting L')(R'), (3) has a built-in directional emphasis circuit that inputs the audio signal and decodes (L)(R)(C)(S) using the Pro Logic surround system. This is a surround decoder. (4
) is a volume control circuit that controls the volume of each output of this surround decoder (3), (5) is an audio output circuit that amplifies the audio signal whose volume is controlled, and (6) is a left channel signal (
L) is applied to the left channel speaker placed on the front left, (7) is applied the right channel signal (R) and is placed on the front right side of the right channel speaker, and (8) is applied with the center channel signal (C). A center channel speaker (9) and (10) are placed at the center of the front, and surround speakers (9) and (10) are placed at the left and right rear, respectively, to which a surround channel signal (S) is applied.

(11) is the input terminal (1) (2) when the test mode is selected by the operation unit (l2) of the remote control transmitter.
) is a test tone circuit that supplies a test tone to the surround decoder (3) instead of the audio signal from the surround decoder (3). This test tone circuit (11) is 500H! A test tone generation circuit (110) that generates a test tone, a first selector switch (111) that supplies this test tone to terminals (0) and (2),
) (2) and (3).
112), an inverter (113) that inverts the output of this second changeover switch (112), and each terminal (0) to ( 3) and a timer circuit (114) that generates a switching signal for sequentially switching.

(13) is a third selector switch that selects the audio signal from the input terminals (1) and (2) or the output of the test tone circuit (11) and supplies it to the surround decoder (3); (l4) is an operation unit (12) inputs an operation command signal and a switching signal from the timer circuit (114),
(15) a microcomputer (hereinafter referred to as microcomputer) that supplies a volume control signal to the volume control circuit (4);
(16) is a color conversion control circuit controlled by a color conversion control signal from the microcomputer (14), (16) is a character display circuit controlled by a color conversion signal output from this color conversion control circuit (15), (17) ) is a CRT that displays on-screen the character display output from this character display circuit (16).

Next, the operation of the above-mentioned circuit in the test mode will be explained with reference to the flowchart of FIG.

First, when the test mode switch of the operation section (12) is operated, this command signal is input to the microcomputer (14) and the test mode is set. That is, the microcomputer (14) controls the character display circuit (16) to display characters as shown in FIG.
Display on-screen on R T (17).

At the same time, the third changeover switch (13) is switched, and the input terminal of the surround decoder (3) is connected to the input terminal of the surround decoder (3).A test tone is generated from the test tone generation circuit (110) in the tone circuit (11), and a test tone is generated from the timer circuit (114). A switching signal is generated. This switching signal switches the first and second changeover switches (111) and (112) at a predetermined period (1
．． 5S) to sequentially switch to terminals (0) to (3).

That is, when the first and second changeover switches (111) and (112) are at the terminal (0), the test tone appears only at the output of the first changeover switch (111), and the surround decoder (3
Since the test tone is supplied to the input terminal L' of the decoder (3), the test tone is demodulated only from the mustard output of the decoder (3). Therefore, only the L channel speaker (6) is driven.

Next, when the first and second changeover switches (111) and (112) are at the terminal (1), test tones of the same phase are input to the input terminals L and R of the decoder (3). A test tone is demodulated from only the C output from the decoder (3), and only the center channel speaker (8) is driven.

Next, when the first and second changeover switches (111) and (112) are at the terminal (2), the test tone is input only to the input terminal R° of the decoder (3).
), the test tone is demodulated from only the R output, and only the R channel speaker (7) is driven.

Furthermore, when the first and second changeover switches (111) and (112) are at the terminal (3), the input terminal L of the decoder (3)
Since test tones with opposite phases are input to ' and R°, the test tone is demodulated only from the S output from the decoder (3) and is sent to the surround channel speaker (9).
)(10) is driven.

As described above, each speaker is sequentially switched and driven every 1.5 seconds.

On the other hand, the output of the timer circuit (114) is
4), this microcontroller (14) determines which speaker is currently outputting the test tone, and based on the determination result, the color conversion control circuit (15)
), and the character display circuit (16) is controlled by the color conversion signal output from the color conversion control circuit (l5). For example, if a test tone is currently being output from the L channel speaker (6), the third
The letters "Front" and "L" for balance in the figure are displayed in a different color from the other letters. Therefore, the user is currently L
When the user knows that the channel speaker (6) is being driven, the user can adjust the volume of the L channel speaker (6) by operating the volume adjustment key on the operation unit (12). In addition, in the screen display of FIG. 3, the volume of each speaker is represented by the number of vertically thick pars.

Further, the on-screen volume display may be as shown in FIG. 4.

Furthermore, in the above embodiment, the speaker from which the test tone is output is indicated by distinguishing the color from other characters, but the display may also be done by changing the brightness or blinking, etc. It is good if it can be identified by changing the display mode. Next, another embodiment in which the test tone circuit is integrated into an integrated circuit (IC) will be described with reference to FIGS. 5 and 6.

In the figure, the part surrounded by the two-dot chain line is an IC test tone circuit (18), and (19) is a 30KHz oscillator (190), which oscillates! (190) output 24576
Frequency divider (191) that divides the frequency and creates a 1.22Hz signal
), T flip-flops (192) (193), D flip-flops (194) (195) and inverters (1
96). (20) is the timing signal (
C. )(C I), the first decoder decodes 8
AND gates (200) to (207) and three OR gates (208) to (210), and output control signals (S,) to (S,).

(22) is controlled by the control signal (S4) and outputs the test tone from the test tone generation circuit (21) as it is when driving the left channel (L) and right channel (R) speakers, and outputs the test tone as it is when driving the left channel (L) and right channel (R) speakers. When driving speakers for surround channel (S), the amplifier (
The first switch circuit (23) and (24) are controlled by control signals (S.) and (S.), respectively, and are composed of a buffer amplifier and a switch. 2. Third switch circuit, (
25) is a fourth switch circuit controlled by a control signal (S,) and composed of an inverter and a switch, and the output of the second switch circuit (23) is controlled by a control signal (S,), and the output of the second switch circuit (23) is controlled by a control signal (S,).
13) to the input terminal of the surround decoder (3) (
The outputs of the third and fourth switch circuits (24) and (25) are combined and input to the input terminal (R°) of the surround decoder (3).

(26) is a second decoder composed of AND gates (260) to (263), and the timer circuit (1
9) Decode the output (C I) (C 1) and send it to the output terminals (T L) (Tc) (T trap) (T s) in sequence.
Derive the “high” output.

Next, the operation of the circuit of this embodiment will be explained.

One of the outputs (C,) (C.) of the timer circuit (19) is decoded by the first decoder (20), and the control signal (S.
1) to (S4) are obtained.

First, at timing (t,), the first switch circuit (22)
The switch is switched to the upper side by the control signal (S4) and the test tone is directly transmitted to the second to fourth switch circuits (23
) to (25). Then, the control signal (S,) ~
(S,) closes the second switch circuit (23) and closes the third switch circuit (23).
The switch circuit (24) is opened and the fourth switch circuit (25
) is open, so a test tone is output only to the output terminal (L).

Next, at timing (t,), the first switch circuit (22
) selects a path that attenuates the test tone by -3 dB, and the second switch circuit (23) is closed, the third switch circuit (24) is closed, and the fourth switch circuit (25) is open. In-phase test tones are output to the output terminals (L') and (R').

Next, at timing (t,), the first switch circuit (22
) again selects the path that outputs the test tone without attenuation, and the second switch circuit (23) is opened, the third switch circuit (24) is closed, and the fourth switch circuit (25) is opened. Therefore, the test tone is output only to the output terminal (R°).

Next, at timing (t4), the first switch circuit (22
) selects the path that attenuates the test tone again, and furthermore, the second switch circuit (23) is opened and the third switch circuit (23) is opened.
4) is open, and the fourth switch circuit (25) is closed, so test tones of opposite phases are output to the output terminals (L') and (R'), respectively.

On the other hand, the timer circuit (19) output (C,) (C
t) is supplied to the second decoder (26), and the timing ([,) (1 1) (1 +) is supplied to each output terminal (T L) (T C) (T I) (T S), respectively. (1 +)
The high output is derived when the microcontroller (14
), this microcomputer (14) can determine which speaker is currently outputting the test tone.

(to) ! According to the present invention, as described above, when the user adjusts the volume of each speaker in the surround test mode, the CR
In order to display which speaker is currently outputting the test tone on the T-hi by changing the display mode,
The drive speaker and its volume can be checked at a glance, making volume adjustment extremely easy.

In addition, incorrect connection of speakers can be easily confirmed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a television receiver according to an embodiment of the present invention, FIG. 2 is a flowchart of the same, and FIG. 3 is a C
FIG. 4 is a diagram showing another embodiment of the display mode on a CRT, FIG. 5 is a block diagram showing another embodiment of the test tone circuit, and FIG. 6 is a diagram showing the same time display mode. It is a chart. FIG. 7 is a circuit diagram for explaining the surround system.

Claims (3)

[Claims] (1) A decoder that decodes a 4-channel audio signal encoded into 2 channels and transmitted to the original 4-channel audio signal, and a volume control circuit that controls the volume of the audio signal from this decoder; A speaker plays back audio signals of four channels whose volume is controlled by the volume control circuit, and a test tone of a predetermined frequency is sent to the speaker of each channel at predetermined intervals in order to adjust the volume level of each of the four channels. What is claimed is: 1. A television receiver comprising a test tone circuit that switches and supplies test tones, the television receiver comprising display means for displaying on a television screen to which speaker of which channel the test tone is currently being applied. (2) a decoder that decodes a 4-channel audio signal encoded into 2 channels and transmitted to the original 4-channel audio signal; and a volume control circuit that controls the volume of the audio signal from this decoder; A speaker plays back audio signals of four channels whose volume is controlled by the volume control circuit, and a test tone of a predetermined frequency is sent to the speaker of each channel at predetermined intervals in order to adjust the volume level of each of the four channels. In a television receiver equipped with a test tone circuit that switches and supplies a test tone, the television receiver includes display means that displays the volume of each channel on the television screen and also displays which channel's speaker the test tone is currently being applied to. A television receiver. (3) The test tone circuit includes: a timer circuit that creates a pair of timing signals with different cycles; a first decoder that decodes the timing signal to create a plurality of control signals; and a test tone with a predetermined frequency. a test tone generation circuit; a switch circuit that is controlled by the control signal and sequentially supplies the test tone to each channel at a predetermined period; and a switch circuit that decodes the timing signal to sequentially drive the speakers of each channel at the predetermined period. 3. The television receiver according to claim 1, further comprising a second decoder that generates switching pulses for the television receiver.