JP2003143495A - Projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital broadcast reception tuner-mounted projection device which is inexpensive and has an analog component video signal input. SOLUTION: The digital broadcast reception tuner-mounted projection device is provided with an external analog video signal input means, a digital television tuner means, a changeover switch means for switching and outputting the signals of these means, a digitizer means (A-D converter) for digitizing the output signals from the switching means, a signal processing means for the digitizer means, and an image display means.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display or a television set having an analog video signal input terminal, and more particularly to a phase of an external or built-in digital television tuner. The present invention relates to a display, a television device, or a signal processing device that switches between a detection signal and the analog video input signal, performs A / D conversion, performs digital image signal processing, and displays an image. 2. Description of the Related Art In digital television broadcasting, different phase modulation systems are used according to the transmission amount and broadcast contents. For example, QPSK modulation is used in CS satellite digital broadcasting, whereas BS satellite digital broadcasting is used. 8PSK is being considered for broadcasting. As a conventional example, FIG. 3 shows a block diagram of a configuration of a CS satellite digital television receiver provided with, for example, an external analog video signal input terminal. In FIG. 3, reference numeral 1 denotes R from an antenna terminal of digital television broadcasting.
F signal input, 2 is a front end (tuner) unit 3, 1st changeover switch 4, 2nd changeover switch 5, 1st AD converter 6, 2nd AD converter 7, 3rd AD converter 8 is external Red signal input terminal 9 is external green signal input terminal 10 is external blue signal input terminal 11 is external vertical synchronization signal input terminal 12 is external horizontal synchronization signal input terminal 13 is synchronization signal processing circuit means 14 is digital demodulation circuit means 15 is MPEG. The demodulation unit 16 is an image signal processing unit 17 is a light valve projection engine 18 is a system controller 101 to 103 An AD converter 19 is a digital switch. In the conventional case, external video signal input terminals 8 to
The external analog video signals of red, green, and blue, respectively, input to
After AD conversion once, it is converted into a digital signal,
The image signal processing means 16 appropriately performs signal processing on the mode signal from the system controller of the input 18 to the 19 digital switch means via the 19 digital switch, and for example, as the R, G, B component signal, the light valve The output is output to the projection engine and the projection display is performed on the screen. On the other hand, the digital television signal is not shown first, but the radio wave of the CS digital television broadcast received by the parabolic antenna is transmitted by one coaxial line to one RF.
The signal is guided to a signal input terminal and supplied to two front end blocks. The front end unit 2 comprises a frequency converter 201 and quadrature detection means 202,
First, the frequency is converted to an intermediate frequency by the frequency converter 201. Next, orthogonal detection is performed by the orthogonal detection means 202. FIG. 2 shows the configuration of the frequency converter 201 and the orthogonal detection means 202. In FIG. 2, the RF signal from 1 is 210
After removing unnecessary low-frequency components by a high-pass filter (HPF), the signal is supplied to the mixer 211. A carrier signal is supplied to a mixer 211 from a local oscillator 212. The frequency of the local oscillator 212 is controlled by the PLL synthesizer circuit 213. From the mixer 211, an intermediate frequency signal (IF signal) having a lower frequency than the input RF signal is supplied to a band-pass filter 214. The signal is amplified by the IF amplifier and supplied to the quadrature detection means 202. In the quadrature detection means 202, first, 2
The IF signal is supplied to 19 PLL circuits to generate carriers. The generated carrier signal is supplied to the mixer 21.
6. On the other hand, the transmission output carrier signal of the PLL circuit 219 is also supplied to the 218 90-degree transfer unit, and the carrier signal shifted by 90 degrees is supplied to the multiplier 217. The IF signals output from the IF amplifier 215 are supplied to the multipliers 216 and 217. By quadrature detection, the I signal component and the Q signal component are obtained from the multiplier 216 and the multiplier 217, respectively. Can be The I signal component from the multiplier 216 is filtered by a low-pass filter (LPF) 220 to remove unnecessary high-frequency components and output an I signal. The Q signal component from the multiplier 217 is filtered by a low-pass filter (LPF) 221 to remove unnecessary high-frequency components and output a Q signal. I from the front end block 2
The signal is input to the A / D converter 5 and the Q signal is input to the A / D converter 6 and quantized, respectively, and supplied to 14 digital demodulation means and error correction means to obtain a digital stream signal and a clock for the digital stream. The digital stream signal and the clock signal for the digital stream are supplied to 15 MPEG demodulating means and are MPEG-demodulated. Here, the sound is also demodulated, but is omitted here. A digital video signal is input to nineteen digital switches from fifteen MPEG demodulation circuit means and selectively supplied to sixteen image signal processing means by the digital switch 19. The image processing means 16 performs image processing, for example, matrix processing for converting an MPEG demodulated signal obtained as color difference signal digital data into R, G, and B primary color signals, other image quality improvement processing, and scanning line conversion. The scalar process to be performed is performed and supplied to the 17 light valve projection engine, and projected and displayed on the screen. However, according to the configuration of the above embodiment, two systems of digitizing (AD converter) means for digitizing an external analog video signal input system and digitizing a tuner output signal. (5 pieces in the conventional example), which is wasteful in cost. In view of the above problems, the present invention provides two systems of digitizing means (AD converter) for digitizing an external analog video signal input system and digitizing a tuner output signal. Are shared through the switching means to provide a cost-effective configuration, and the signal processing circuit for the external analog video signal input system and the signal processing circuit for the tuner output signal are integrated after the common digitizing (AD converter) means. Thus, digital signal processing can be performed, and the digital signal processing circuit can be made into one chip and cost can be reduced. Embodiments of the present invention will be described below in detail with reference to the drawings. [First Embodiment] FIG. 1 shows a first embodiment of the present invention.
With an analog video signal input terminal according to the embodiment, is a circuit block of a digital television device,
FIG. 3 is a diagram best representing the features of the present invention. In FIG. 1, reference numeral 1 denotes R from an antenna terminal of digital television broadcasting.
F signal input, 2 is a front end (tuner) unit 3, 1st changeover switch 4, 2nd changeover switch 5, 1st AD converter 6, 2nd AD converter 7, 3rd AD converter 8 is external Red signal input terminal 9 is external green signal input terminal 10 is external blue signal input terminal 11 is external vertical synchronization signal input terminal 12 is external horizontal synchronization signal input terminal 13 is synchronization signal processing circuit means 14 is digital demodulation circuit means 15 is MPEG. The demodulation means 16 is an image signal processing means 17, the light valve projection engine 18 is a system controller. First, although not shown, the radio wave of the CS digital television broadcast received by the parabolic antenna is guided to one RF signal input terminal by a coaxial line and supplied to a front end block of two. The front end unit 2 comprises a frequency converter 201 and quadrature detection means 202.
First, the frequency is converted to an intermediate frequency by the frequency converter 201. Next, orthogonal detection is performed by the orthogonal detection means 202. FIG. 2 shows the configuration of the frequency converter 201 and the orthogonal detection means 202. The front end 2 receives a digital modulation signal of 1 GHz band from an outdoor unit (not shown) from an input terminal 1 and removes and amplifies unnecessary waves by a high pass filter 210 and a preamplifier and a tunable filter (not shown). This is performed and input to the mixer 211. The frequency converting means including the mixer 211, the first oscillator 212, and the frequency synthesizer 213 allows a clock terminal 103 of the frequency synthesizer from a control microcomputer (not shown) of the receiver.
The desired channel is converted to an intermediate frequency of, for example, 479.5 MHz by the information added to the data terminal 104 of the frequency synthesizer, and the output of the mixer 5 is passed through a band-pass filter of 214 and an IF amplifier of 215 to obtain a quadrature detection means. Are supplied to a first mixer 216 and a multiplier 217. The output of the second oscillator 219 is provided as a first carrier signal to a first multiplier 216. On the other hand, the output of the second oscillator 219 is further supplied to a 90-degree phase shifter 218 and is output as a second carrier signal having a 90-degree difference generated by the phase shifter 218.
Supplied to The signals are multiplied by multipliers 216 and 217, respectively, and RF-filtered by low-pass filters 220 and 221 respectively.
As the outputs of the quadrature detection means from which the components have been removed, the output of I is output from 222 and the output of Q is output from 223. The I signal obtained from the front end 50 is supplied to the changeover switch 3, and the Q signal is supplied to the changeover switch 4. The switches 3 and 4 are switched under the control of the system controller 18. Now, the switches 3 and 4 are connected to the front end side, and the I output signal is supplied to the AD converter 5 and the Q output signal is supplied to the AD converter 6. In AD converters 5 and 6, the respective supply signals are quantized and supplied to 14 digital demodulation means and error correction means to obtain a digital stream signal and a clock for the digital stream. The digital stream signal and the clock signal for the digital stream are supplied to 15 MPEG demodulating means,
Demodulated. Here, the sound is also demodulated, but is omitted here. The video signal is supplied from the 15 MPEG demodulation circuit means to the 16 image processing means. The 16 image processing means selectively performs image processing, for example, matrix processing for converting an MPEG demodulated signal obtained as color difference signal digital data into R, G, and B primary color signals, other image quality improvement processing, and scanning line conversion. Perform scalar processing etc. 17
To supply light valve projection engines. In the 17 light valve projection engine, necessary signal processing is appropriately obtained and an image is projected on a screen. Next, by switching the input switching mode of the present apparatus to the external R, G, B input mode, 18
The switch 3
And 4 select the external input terminal, and the red signal input to the R signal input terminal of 8 is supplied to the AD converter of 5 and the G signal of 9
The green signal input to the signal input terminal is supplied to each of the six AD converters. The blue signal input to the B signal input terminal 10 is supplied to the AD converter 7 as it is. Here, a level adjustment by a preamplifier, a pre-filter process, a clamp process, and the like are required between each of the R, G, and B signal input terminals and each AD converter 5.6.7. However, since it is general, it is not specifically described here. Next, the input signals of red, green and blue are quantized in the 5.6.7 AD converters respectively, and the output is input to the second input system of the 16 image processing means. It performs image processing such as image quality improvement processing and scalar processing for converting scan lines, etc., and supplies it to the 17 light valve projection engine. In the 17 light valve projection engine, necessary signal processing is appropriately obtained and an image is projected on a screen. As described above, according to the present invention, the digitizer for digital demodulation at the subsequent stage of the front end for receiving digital broadcasting, and the R, G, and
A digitizer for digitizing an image from the B input terminal can be used in common, so that expensive AD converters can be reduced and cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a configuration of a digital television device. FIG. 2 is a block diagram of a front end unit. FIG. 3 is a block diagram showing a configuration of a conventional digital television device. [Description of Signs] 1 R from antenna terminal of digital television broadcast
F signal input 2 Front end (tuner) unit 3 First changeover switch 4 Second changeover switch 5 First AD converter 6 Second AD converter 7 Third AD converter 8 External red signal input terminal 9 External green signal Input terminal 10 External blue signal input terminal 11 External vertical synchronization signal input terminal 12 External horizontal synchronization signal input terminal 13 Synchronization signal processing circuit means 14 Digital demodulation circuit means 15 MPEG demodulation means 16 Image signal processing means 17 Light valve projection engine 18 System controller

Claims (1)

Claims 1. At least an external analog baseband video signal input terminal, AD converter means for digitizing the analog baseband video signal, and means for processing an output signal of the AD converter and displaying the image on a display Tuner means for selectively receiving a digital television signal; quadrature detection means for quadrature detecting the output of the tuner means; signal switching for switching between the quadrature detection output signal and the analog baseband video signal to be supplied to an AD converter. Means for processing the output signal of the A / D converter to display an image on a display digital television, and switching between the analog baseband video signal and the output of the quadrature detection means of the digital broadcast receiving unit. Switch with switch, AD change A display device or a television device, wherein the A / D conversion unit shares the quantization of the output of the quadrature detection unit of the analog baseband video signal and the digital broadcast receiving unit. An image processing device connected to the device.