 |
Description  |
|
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to controlling a television receiver with a remote commander and, specifically, to controlling a television having the picture-in-picture feature.
2. Description of the Background
Recently television receivers are equipped with various functions, such as the so-called picture-in-picture function and the ability to preset a TV channel program for viewing or recording. In the picture-in-picture function, the overall area of
the screen is selected as a main screen, and a portion of this main screen is selected as a sub-screen on which pictures or images of another TV channel are displayed. Recent television receivers also include a built-in satellite broadcasting tuner to
receive satellite broadcasting programs.
In addition, a recent television receiver has been proposed in which, after a mechanical switch is switched on to place it into a standby state, the main power to the receiver can be switched on or off by a remote controller. When the main power
is switched on, each of the tuners for the VHF/UHF and the satellite broadcast is supplied with power and carries out its receiving and transmitting operations. On the other hand, when the main power is switched off, the supply of the power to each of
the tuners for VHF/UHF and for the satellite broadcast is de-energized, and the receiving and transmitting operations thereof are stopped.
The television receiver described above also enables a desired reserved program to be received at a desired reserved time, and also can perform various settings such as a color adjustment setting, a volume adjustment setting, and the like by
manipulation of a remote controller. Desired ones of the above items are displayed on the screen of the cathode-ray tube of the television receiver, and then parameters for the displayed items are set.
Also in a recent television receiver, various functions are improved by displaying the contents of operations, the operation sequences, and the receiving conditions for various functions in displays called menus. These menus are displayed on the
sub-screen, for example, in order to simply utilization of these functions by a user. An attempt is made to improve the man-to-machine interface function.
When the operation of the menu display is performed by a user, the setting items with regard to the plural functions provided by the television receiver are first displayed on the sub-screen. A selection is then made of one of these plural
setting items by employing a cursor moved by operation of the remote controller. The new setting items, for example, the contents of the operation and sequence of operations, are displayed. Next, when the user wants to register a recording reservation
of a desired TV program for example, the recording start and stop times and the channel number are set by the user.
To confirm the contents of the setting items selected by the user, when one of the plural setting items is selected, the color of this selected item is changed, blanked, and highlighted. Nevertheless, the color changing, blanking, and
highlighting of these known television receivers does not make it easy for the user to confirm the selected operations.
Another proposed television apparatus displays only selected items without other setting items, but it is nevertheless necessary for the receiver to prepare an image for displaying all items in order to display only selected items. This results
in the drawback that a large amount of memory capacity is needed for displaying a menu.
Simplification of operation of recent television receivers is also desired. One proposal for such simplification, is to display a sequence of a menu on the screen, select the desired item by a moving cursor, and display the selected item for
parameter setting. But in this menu setting method, particularly when moving the cursor on the screen by a remote controller, the cursor is frequently moved incorrectly, because of differences in the timing of transmission of operation data from the
remote controller to the television and the timing of the scanning screen of the menu. Moreover, when the reserving operation is performed, if the user performs another operation, there is the possibility of mistake, for example, the undesired deletion
of a parameter.
OBJECT AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a television receiver that overcomes the above drawbacks inherent in previously proposed receivers.
According to one aspect of the present invention, a television receiver can support many features without losing ease of operation, and provides a very easy-to-see-display. For example, the menu is in common with many items of operations and
only a small amount of memory capacity is needed. It then becomes easy to select an item by moving the cursor, and it is easy for the user to recognize which item is selected and operated correctly, and to prevent mistakes in erroneously changing
parameters.
The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, to be read in connection with the accompanying drawings, in which
like reference numerals represent the same or similar elements.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a television receiver comprising a VHF/UHF tuner, a BS tuner, a signal selector, and a controller formed by a microcomputer according to an embodiment of the present invention;
FIG. 2 is a block diagram of a television receiver according to another embodiment of this invention that receives a control signal from a remote controller for moving a cursor relative to a menu on the screen of the receiver;
FIG. 3 is a plan view of a remote controller for use with the television receivers of FIGS. 1 and 2;
FIG. 4 consists of images showing a main screen and a sub-screen on the cathode-ray tube of the receivers of FIGS. 1 and 2;
FIG. 5 is a view of a menu display on a screen of the television receivers of FIGS. 1 and 2;
FIG. 6 consists of views of other menu displays on a screen of the television and showing half-tones and a cursor;
FIG. 7 is a schematic of a circuit of the television receiver of FIGS. 1 and 2 for controlling the display on the sub-screen;
FIG. 8 is a view of another menu showing a main menu and a hierarchy thereof;
FIG. 9 is a view of another menu showing an n.sub.th hierarchy thereof;
FIG. 10 is a flow chart of a method of moving a cursor of the television screen according to this invention;
FIG. 11 is a flow chart a of method of moving a cursor for selecting an item on the screen;
FIG. 12 is a flow chart of a method for changing the color of a displayed menu;
FIG. 13 is a view of a display operation for reserving or confirming timer operation and recording;
FIG. 14 is a flow chart of a method for selecting the menu on the sub-screen of the television receiver of FIGS. 1 and 2;
FIGS. 15 and 16 are views showing the displayed menu when the color of a selected, displayed item changes; and
FIGS. 17 and 18 are views showing the displayed menu when a half-tone color display of an item indicates that the item is not available.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 is a block diagram of a television receiver according to an embodiment of this invention including a VHF/UHF receiving section for receiving NTSC color television signals and sound signals, and a receiving section for receiving signals
from a broadcast satellite (BS) or from a communication satellite (CS). A control section controls and selects signals and a sound section reproduces the sound at a loudspeaker.
In the VHF/UHF receiver 12, to which a Yagi antenna 11 is connected, the desired channel from the VHF/UHF band is selected and the color video signal and audio sound signal are produced.
The satellite broadcast receiver is connected to a parabola antenna 21 that receives the 12 GHz signal broadcast by the satellite, and the received signal is converted in frequency to a 1 GHZ signal using a BS converter 22. The converted signal
is fed to a broadcast satellite tuner 23 that selects the desired channel, performs automatic gain control (AGC), IF amplitude, FM demodulation, de-emphasis, and reduction of an energy dispersal signal. The BS tuner 23 reproduces the video signal and
audio signal modulated by pulse shift keying (PSK) and pulse code modulation (PCM). When the A mode of BS broadcast is received, the BS tuner 23 reproduces four channels of PCM sound signals, and when the B mode is received, the BS tuner 23 reproduces
two channels of PCM signals. A PSK demodulator 25 demodulates the signal and also detects the scrambling state of the signal, and a digital to analog (D/A) converter 26 converts the PCM digital audio signal from the PSK demodulator 25 to an analog sound
signal. A level detector 27 detects the level of the received signal at the BS antenna 21 by detecting the output signal of the BS tuner 23 in the 8 MHz band. The tuned signal output from the BS tuner 23 is also fed to output terminals 28a, 28b, and
28c to external decoders. The BS tuner 23 is also connected to an input terminal 28d for receiving keyed AFC pulse from the MUSE signal.
The BS receiving section including the BS tuner 23 selects the desired channel and supplies the signal to the output terminals when the received signal is scrambled or when it is a MUSE format signal. If the received signal is some other sort of
signal, it does signal processing as if it were an NTSC signal and changes over the sound signal to two channels corresponding to the video signal or two channels not corresponding to the video signal.
A MUSE down converter 51 can be connected for use in receiving a MUSE format signal (multiple sub-Nyquist encoding) to reproduce an HDTV signal. This HDTV signal is a TCI luminance and chrominance signal and a PCM sound signal. A Japanese
Satellite Broadcast (JSB) decoder 52 can be connected for decoding a JSB scrambled broadcasting signal, and a communications satellite (CS) decoder can be connected for decoding a scrambled signal broadcast by a communications satellite.
The respective signals at output terminals 31a, 31b, 31c, 31d, 31e, and 31f from the MUSE down converter 51, JSB decoder 52, and CS decoder 53, as well as outputs from the VHF/UHF tuner 12 and the video processing circuit 24 are selected for
display by an audio-video (AV) switch 32. The AV switch 32 also selects audio signals from the VHF/UHF tuner 12, the D/A converter 26, the MUSE down converter 51, the JSB decoder 52, and the CS decoder 53. A video processing circuit 33 processes the
color television signal selected by the AV switch 32 to an RGB signal for display. A picture-in-picture circuit 34 performs the necessary picture-in-picture processing in the well-known manner. An RGB switch switches the RGB signals from the
picture-in-picture circuit 34 in response to a signal from the control section. A cathode-ray tube 36 displays the images of the selected signal, and an audio processing circuit 37 processes the audio to provide tone control and the like for
reproduction over a loudspeaker 38. Output terminals 31g, 31h supply audio and video signals to an optional VTR 70 for recording. Similarly, input terminals 31i, 31j receive video and audio signals from the optional VTR 70 for playback.
The video processing circuit 33 supplies the video signal to the cathode-ray tube 36 and the audio processing circuit 37 supplies the audio signal to the loudspeaker 38. When the signal of the selected channel is scrambled, these circuits
operate for displaying and reproducing the unscrambled video and audio signals, respectively, from the JSB decoder 52. These terminals supply the color television signal and the audio signal selected by the AV switch 32 to the VTR 70 and, if necessary,
for displaying picture-in-picture, the menu of operation, and the contents of the many functions and settings.
The system controller 41 controls the outputs based on the detected scrambled state of the PCM sound signal from the PSK demodulator 25 and on the state of the color television signal from video processing circuit 33. A memory 42 stores the
control program and other operating settings set by the user. A BS microcomputer 43 controls the channel selection of the BS tuner 23. A digital-to-analog (D/A) converter 44 converts data from the system controller 41 to analog signals for controlling
the volume of the reproduced sound. The display microcomputer 45 controls a menu display based on data from the system controller 41. A receiver 47 receives infrared radiation control signals from the remote controller 60. The system controller 41,
the video processing circuit 33, the picture-in-picture circuit 34, the audio processing circuit 37, and the memory 42 are connected to each other by an I.sup.2 C bus.
In the similar television receiver of FIG. 2, an antenna 11 receives a VHF/UHF television signal and supplies it to the tuner 12. Tuner 12 is used to select the desired channel in response to a control signal from a controller 41 formed of a
microcomputer that includes a video RAM, a ROM, and an additional RAM, all of which are internal. The controller 41 supplies control signals based on channel information signals supplied from a control panel 18 and from a remote controller 420 through a
receiver 419. The controller 41 also memorizes parameters set by the user in a ROM 417 and performs many other operations synchronized by an oscillation signal from an oscillator 416a.
The tuner 12 changes the frequency of the television signal to the IF signal frequencies, 58.75 MHz in the video and 54.25 MHz in the audio, respectively. These IF signals are amplified, detected, auto-gain controlled, and then supplied to the
AV switch 32. The AV switch 32 supplies video and audio signals from an input terminal group 31, the tuner 12, and a BS receiver 422 to the video processing circuit 33 and to the audio processing circuit 37 under control of a signal from the controller
41.
The VTR 70 is connected to the input terminal group 31 and to the output terminal group 31' for both video and audio signals.
The video processing circuit 33 separates the chrominance signal from the composite video signal and generates a color difference signal. The video processing circuit 33 then generates RGB signals and supplies these signals to the cathode-ray
tube 36. The video processing circuit 33 also generates deflection signals for vertical and horizontal deflection fed to vertical and horizontal deflection coils not forming a part of the present invention. The video processing circuit 33 also supplies
the RGB signals for displaying control characters on the cathode-ray tube 36 under the control of the controller 41. An audio processing circuit 37 processes the audio signals and supplies them to the loudspeaker 38.
BS receiver 422 receives the satellite broadcast signal, for example, 12 GHz signal, through a parabola antenna 21. The BS receiver 422 receives the FM TV signal and changes the frequency to the 1 GHz intermediate frequency (IF). The BS tuner
23 selects the band of the IF signal in response to control signals from the controller 41 as determined by the control panel 418 or the remote controller 420 and FM demodulates and supplies the demodulated signal to a video processing circuit 24 and to
an audio processing circuit 25, respectively.
Video processing circuit 24 processes the FM video signal and supplies a demodulated signal to the AV switch 32. The audio processing circuit 25 demodulates and converts to analog the 4-phase DPSK audio signal and feeds the processed audio
signal to the AV selector switch 32. A power supply 421 energizes the main portion 410 of the television receiver and the BS receiver section 422. The power supply 421 is connected by a plug 424 to a source of AC power. This power supply 421 supplies
power to the system. When a switch 415 connected to the microcomputer 41 is operated the microcomputer 41 is energized by power converted by a transformer 425 and placed in stand-by. In the case of watching TV or recording signals by a VTR, the user
operates switches on the control panel 418 or on a remote controller 420. By pushing power key 420a on remote controller 420 an infra-red signal is received through receiving unit 419 and fed to the microcomputer 41 to control the power supply 421. By
pushing change input key 420b, the AV selector switch 32 selects an input signal from the tuner 12, the BS tuner 23, or from the input terminal group 31 under control of the microcomputer 41. Each stroke of the change input key 420b sequentially changes
the outputs of the video and audio on the cathode-ray tube 36 and the speaker 38. By pushing channel changing key 420c, if the + key is pushed then the channel number increases and if the - key is pushed then the channel number is decreased. The
channel number signal is also supplied to the microcomputer 41. Tuner 12 and BS tuner 23 select the channel and the desired image of signal is displayed on the screen of the cathode-ray tube 36 by using the channel changing key 420c. When operating the
volume key 420d, if the + key is pushed then the sound volume increases and if the - key is pushed then the sound volume decreases. By pushing the menu key 420e, menu data is written into the video RAM in the microcomputer 41 and this data is read out
and supplied to the cathode-ray tube 36 through video processing circuit 33 as RGB signals, and the menu is displayed. This data in the video RAM is read from a ROM that is also a part of the microcomputer 41.
FIG. 3 shows the configuration of the keys of the remote commander 60 shown in FIG. 1. Menu switch 61 displays the menu on the sub-screen of the cathode-ray tube 36. Cursor switches 62, 63 move the cursor left to right or top to bottom on the
screen for selecting one of the items of the menu. Decision switch 64 selects the item indicated by the cursor. Power switch 65 operates the power supply of the television set. Input changing switches 66, 67, 68 select the input source for display.
Numerical keys 69 change the channel numbers. Thus, the remote controller 60 selects a channel desired by the user and selects a color television signal from the video processing circuit 24 by operating the AV switch 32, and displays the image on the
cathode-ray tube 36. The remote controller selects a sound signal from the D/A converter 26 by operating the AV switch 32 and outputs the sound through speaker 38. For example, in mode A, the television sound or an independent sound is selected and in
mode B it selects the television sound. The received video signal is supplied to the JSB decoder 52 if the PCM sound channel is determined to be scrambled. The signal decoded by the JSB decoder 52 is then fed through the AV selection switch 32 and
displayed on the cathode-ray tube 36 and the sound is reproduced by the speaker 38. When the received signal is not scrambled it is supplied directly to the CRT and the speaker and not through the JSB decoder 52. If the independent sound mode is
selected and the user selects a blank picture mode, the control section controls the power supply to interrupt power to the video processing circuit 33 and the cathode-ray tube 36, and to provide power to the BS converter 22, the BS tuner 23, the PSK
demodulator 25, the D/A converter 26, the audio processing circuit 37, and the system controller 41.
If the user sets the channel reservation mode to avoid failing to view or record a program by later selecting an undesired channel, the control section selects the predetermined BS channel, and outputs color video signal and sound signal to the
VCR 70 through the output terminals 31g, 31h respectively and inhibits channel selection if the user subsequently tries to change the channel, for example, by operating the remote controller 60.
If the user operates the remote controller 60 to display the menu on the screen, the control section controls the display microcomputer 45 for displaying a sequence for recording a BS signal, for example, in the sub-screen. If the user operates
the remote controller 60 to perform the picture-in-picture mode, the control section controls the AV switch 32, and the picture-in-picture circuit 34 for displaying the BS program on the main screen and a VHF/UHF TV program in the sub-screen, for
example. More specifically, when the user sets the channel number for viewing a VHF/UHF television broadcast by using the numerical keys 69 of the remote controller 60, the system controller 41 receives the channel number signal from the remote
controller 60, controls the VHF/UHF tuner 12 to selects the set channel, and controls switches 32a, 32c for selecting the video and audio signals from the tuner 12, respectively. The video processing circuit 33 supplies the RGB signal converted from the
color video signal fed by switch 32a to the cathode-ray tube 36. The audio processing circuit 37 supplies the audio signal to the speaker 38 with suitable processing, such as tone control. Thus, the user can watch the desired program on the VHF/UHF
band.
For confirming the contents of the operations set by the user, the system controller 41 supplies channel number data to the display microcomputer 45 through the I.sup.2 C bus. The display microcomputer 45 supplies an RGB signal, for displaying
the channel number at the upper-right edge on the screen, for example, to the video processing circuit 33 through the RGB switch 35. The video processing circuit 33 superimposes the RGB channel number onto the image of the broadcast program of the
VHF/UHF band.
When the user sets the BS channel by using the remote controller 60, the system controller 41 receives a control signal from the remote controller 60, controls the BS tuner 23 to select the BS channel, and detects whether the received program is
an NTSC or hi-vision (HDTV) signal based on the state of synchronization of the PCM sound signal from the PSK demodulator 25 or based on the signal level at the level detection circuit 27. If an NTSC signal is detected, the system controller 41 controls
the AV switch 32 to select the signal from the video processing circuit 24 and the signal from the D/A converter 26. If a hi-vision signal is detected, the system controller 41 controls the AV switch 32 to select the signal from the MUSE down converter
51.
In the normal mode, the analog sound signal is converted to a PCM signal and modulated by PSK, and then frequency division multiplexed. In the hi-vision mode, the sound signal is converted to special differential PCM signal and TCI modulated in
the period of the vertical synchronization signal. The system controller 41 detects that the signal is an NTSC signal if the received level at the level detection circuit 27 is high and it detects the synchronization signal of the PCM sound signal. It
is decided that the received signal is a hi-vision signal if the received level is high and the synchronization is unlocked. Detection of a normal signal or hi-vision signal is also made based on the presence of a keyed AFC pulse supplied by MUSE down
converter 51 to the BS tuner 23 through the input terminal 28d.
The selected color video signal is supplied to the video processing circuit 33, and the selected audio signal is supplied to the audio processing circuit 37, so that the user can watch each channel by only the desired setting channel in spite of
the kind of BS program mode.
When the user operates the remote controller 60 for displaying VHF/UHF program on the sub-screen at the time of watching a BS program, the system controller 41 receives a control signal corresponding to the picture-in-picture operation from the
remote controller 60, controls the VHF/UHF tuner 12 for selecting the set channel, and controls the switch 32b for selecting the color video signal from the VHF/UHF tuner 12. The selected color video signal is supplied to the picture-in-picture circuit
and converted to the RGB signal and supplied as a signal for the sub-screen to the video processing circuit 33 through the RGB switch 35. In this way, the user can watch a BS program on the main screen and a VHF/UHF program on the sub screen.
If the user sets the channel to a scrambled channel of the BS, the system controller 41 detects the scrambled state of the program based on a state of the PCM sound signal from PSK demodulator 25 and selects color video signal from the video
processing circuit 24 and sound signal from the D/A converter 26, if the program is not scrambled. When the program is scrambled, it selects the color video and audio signal from the JSB decoder 52. When the user wants to listen to the sound of the
independent sound program, if the sound signal of the television is scrambled, it selects the independent sound signal from the JSB decoder 52, and if the sound signal of the television is not scrambled, it selects the independent sound signal from the
D/A converter 26. The number of combinations of scrambled and not scrambled programs is four, because there are scrambled and not scrambled states in the television sound signal (the same as video signal), and there are scrambled and not scrambled
states in the independent sound signal. When the television sound signal is selected, the system controller 41 performs control based on the scrambled state of the television sound signal, and the user can watch both scrambled and non-scrambled programs
without manually changing the mode. When the independent sound signal is selected, the system controller 41 performs control based on the scrambled state of the television sound signal and the independent should signal, and the user can listen in each
case without manually changing the mode.
If the video signal is not scrambled, or if the video signal is scrambled and the non-display picture mode is selected, the signal path is not thorough the JSB decoder 52, so the sound quality is not damaged by passing through many circuits. The
decision as to whether the program is scrambled or not is based on the 12th bit of a group of control bits of the PCM sound signal that shows the state of scramble of the video signal.
When the user sets a channel in the CS broadcasting system by using the remote controller 60 for listening to a music program, for example, the system controller 41 receives the control signal from the remote controller 60, controls the BS tuner
23 to select the set channel, and detects whether it is scrambled or not based on the state of the PCM sound signal from the PSK demodulator 25. If the not scrambled state is detected, the AV switch 32 is controlled to select a sound signal from the D/A
converter 26. On the contrary, if a scrambled signal is detected, the AV switch 32 is controlled to select the sound signal output from the CS decoder 53. The sound signal of a nonscrambled program is converted to PCM signal and PSK duplex frequency
modulated, and the sound signal of a scrambled program is first scrambled, PCM converted, and then PSK duplex modulated. The system controller 41 detects the scrambled or nonscrambled states based on the 8th bit of a range of bits from the PSK
demodulator 25. The selected sound signal is supplied to the audio processing circuit 37, and the user can listen to the desired program without noticing whether the program is scrambled or not. According to this invention, the mode conversion of a
scrambled or nonscrambled signal is not only enabled automatically as described but also permits manual selection using the remote controller 60.
When the user presses the menu switch 61 of the remote controller 60, the system controller 41 receives a control signal for displaying the main menu relating to each functional setting, and supplies corresponding data to the display
microcomputer 45 for displaying the main menu. The characters used for displaying the main menu can be stored in the memory 42 and output onto the I.sup.2 C bus. The display microcomputer 45 displays the main menu on the sub-screen 36b, which is a part
of the main screen 36a of the face of the cathode-ray tube 36 shown in FIG. 4b, based on this data from memory 42.
FIG. 5 shows the main menu display including a display setting parameter 36b.sub.1 of the sub screen in the picture-in-picture operation, a parameter 36b.sub.2 for setting picture and sound qualities, a parameter 36b.sub.3 for changing over the
sound in the BS receiving mode, a parameter 36b.sub.4 for setting the recording reservation, a parameter 36b.sub.5 for setting the change-over of a bilingual sound mode, and a cursor 36b.sub.0. The display microcomputer 45 supplies an RGB signal for
displaying the setting parameters and cursor to the video processing circuit 33 through the RGB switch 35.
The video processing circuit 33 converts the color video signal at the AV switch 32 to the RGB signal, switches this RGB signal and the RGB signal from the RGB switch 35, displays the picture based on the signal from the AV switch 32a on the main
screen 36a and displays the picture based on the RGB signal from the RGB switch 35 on the sub screen 36b, as shown in FIG. 4b.
The user can move the cursor 36b.sub.0 by pushing cursor switches 62, 63 of the remote controller 60 while watching the displayed menu. If the user pushes the enter switch 64, the setting parameter pointed to by the cursor 36b.sub.0 is selected,
and a new menu is displayed corresponding to the selected parameter.
When the user selects from the main menu of FIG. 5 the sub-screen parameter 36b.sub.1, two sub screens 36b, 36c are displayed at the same time at the lower part of the main screen 36a, as shown in FIG. 4C. A color video signal from one of the
video processing circuit 24 or the VTR 70 is selected by the switch 32b of the AV switch 32, and the selected picture is displayed on the sub-screen 36c.
The sub-screen menu is displayed on sub-screen 36c and as shown in FIG. 6a includes menu item 36b.sub.11 for returning sub-screen display to the main menu, item 36b.sub.12 for setting the source of the display on sub-screen 36c, item 36b.sub.13
for setting the course channel, item 36b.sub.14 for setting the sound volume corresponding to the picture in sub-screen 36c at the earphone output terminal, item 36b.sub.15 for swapping the pictures in the main screen 36a and the sub-screen 36c, item
36b.sub.16 for setting the position of the sub-screen 36c on the main screen 36a, item 36b.sub.17 for setting the size of the sub-screen 36c, and a cursor 36b.sub.10. As a result, the user can set new parameters of the sub screen 36c, while confirming
the displayed picture on the sub-screen 36c. For example, when the user elects to swap the main and sub screen displays by selecting item 36b.sub.15 using the cursor switches 62, 63 and the enter switch 64, the system controller 41 swaps the images of
the main screen 36a and the sub-screen 36c, controls the AV switch 32, and stores setting parameter in the memory 42.
The system controller 41 dims all other items being displayed except the selected setting parameter. This is the so-called half-tone and in the example of FIG. 6b all items except item 36b.sub.15 are shown dimmed by the dotted background. The
data for dimming is sent by controller 41 to the display microcomputer 45 by the I.sup.2 C bus. The display microcomputer 45 controls the reduced RGB signal levels of all items except the swap item 36b.sub.15 to the video processing circuit 33 through
the RGB switch 35.
An embodiment for accomplishing this display dimming is shown in FIG. 7. The circuit for varying the output level of the display microcomputer 45 comprises resistors for DC bias 81R, 82R, resistors for matching output impedance 83R, 84R, and a
resistor for varying the output level 85R. Resistors 81R, 82R are connected in series between a power source and ground. Resistors 83R, 84R are connected in series between the output of the red (R) signal of the display microcomputer 45 and an output
terminal 86R. Resistor 85R is connected to a point between a signal output I of the display microcomputer 45 and output terminal 86R. When the dimmer mode is generated, the display microcomputer 45 shifts the level of signal I to low. Normally, the
level of that signal I is high or open circuited. As a result, the level of the R signal supplied to the RGB switch 35 through the output terminal 86R is reduced. The blue (B) and green (G) signals are controlled the same as the R signal, and level
controlled RGB signals are supplied to the video processing circuit 33. After that all items except the swap item 36b.sub.15, for example, are dimmed, and the user can confirm the selected setting item easily.
In this | | |
