-1- Figure 1. Central Processing Unit Block Diagram Signal Processing
-2- Figure 2. Signal Processing Block diagram
DX4P TG Y/C Separator The Importance of a Comb Filter The luminance and chroma information are mixed in bandpass filter limits the amount of usable luminance the composite TV signal and must be separated so the information and lowers the picture resolution. TV can properly use each portion. A color TV that does A comb filter separates the luminance and chroma in a not have a comb filter can separate the luminance from different, more selective method which allows the TV to the chroma by using a bandpass filter. However, a use more of the luminance and maintain more detail.
Figure 3. Y/C Separation Block Diagram
The Y/C separator uses the configuration shown in The diagonal resolution improvement circuit improves Fig. 3. After a non delayed signal, a 1H delayed signal, the diagonal resolution of the Y signal. Meanwhile, 3 and a 2H delayed signal pass through band pass filter line C passes through the cross color canceller and is BPF1, they enter a 3 line comb filter. The 3 line comb output as a C signal. filter outputs a C signal called 3 line C. The output The C signal BPF and Y signal notch filter signal of the dot canceller switches BPF-C which is the characteristics can be switched between narrow band C signal output from 3 line C and BPF-1 and outputs a and broad band. Both become broad band using 0 and Y signal. narrow band using 1.
DX4P TG -3- RGB Signal Processing
-4- Figure 4. RGB Signal Flow Block diagram
DX4P TG RGB signal processing White Character Correction Circuit OSD Insertion Circuit White character correction expresses clear white 1. Input signal characters by increasing the B-Y signal level of areas Color is displayed using three signals, 4 bit, R,G where there is no color and the brightness level is high, and B. 4096 colors can be displayed. The OSD and converting to a whiter telop character. signal can be inserted at a synthesis ratio with any video signal according to the a blending signal (4 Black Level Correction Circuit bits) from the microcontroller. The video signal is The black level correction circuit detects the blackest output when the a blending signals are all low. area (minimum value) in a screen, and when the blackest area is above the pedestal level, the circuit 2. Contrast and brightness linking does expansion correction of the gradation area under The OSD contrast and brightness control is linked the black level correction start point in the black to the contrast and brightness control of the main direction so that the blackest area is at the pedestal video signal. level. Brightness Control Circuit Dynamic Gamma Correction Circuit Brightness control is a function that controls the offset The dynamic gamma correction circuit detects the level of a signal. As data processing for this LSI, the whitest area in a screen after gamma correction, and pedestal level of the Y image quality correction circuit when the whitest area is greater than the blooming done with a YUV signal is set adding or subtracting the level set, the circuit operates so that the whitest area offset control value of the Y signal. matches the blooming level. Blanking Signal Generating Circuit R-Y Demodulation Axis Control Circuit The blanking signal generating circuit and blanking R-Y demodulation axis control is a function to control signal insertion circuit perform super blanking the color reproducibility to its optimal level to match the processes on output RGB signals. Super blanking light emitting characteristics of the display device. makes the retrace line invisible even if the brightness Control is done by turning the R-Y axis with the angle control is raised to the maximum by lowering the video of the B-Y signal fixed. signal to a level of the pedestal level or lower during the horizontal and vertical blanking period when driving a B-Y Demodulation Gain Control Circuit video display device. B-Y demodulation axis control is also a function to control the color reproducibility to its optimal level to Drive and Cutoff Control Circuit match the light emitting characteristics of the display The drive control circuit has 12 bit drive control value device. Control is done by changing the B-Y signal gain for each RGB, and 12-bit video signals undergo from 0 to 2x with the R-Y signal gain fixed. amplitude control as is and are output as 12 bits. The cutoff control circuit controls cutoff by adding and RGB Conversion Matrix Circuit subtracting 12-bit cutoff control data to a 12 bit video For all functions processed by a YUV signal, all signals signal. for which all processes have ended are converted to an RGB signal, and ultimately are made into signals for VM Drive Signal Generator Circuit driving a CRT. VM (Velocity Modulation) signals clearly represent the contours of a video image by changing the electron The conversion formula for this is as follows. For beam speed in the contour areas. VM signals are NTSC, PAL SECAM, 525P, and 480P formats, RGB generated from a brightness signal with the edge signals are converted based on: corrected by the horizontal contour correction circuit standing. A VM signal is a brightness signal that has B = Y + Pb / 0.564 undergone primary differentiation, but noise is not R = Y + Pr / 0.713 highlighted, so coring processing and a limiter process G = (Y - 0.114B - 0.299 R) / 0.587 for controlling the effect are required.
Video image brightness signal
VM Signal VM noise level control
VM Signal Generation RGB Matrix Processing DX4P TG -5- ABL Voltage Control The ABL voltage (beam current volume) undergoes A/D conversion and the following controls are performed.
1. DC transit level correction: This raises the 3. White character correction ABL control: When the brightness level according to the increase in beam beam current volume is high, this automatically current volume to prevent black fill in. eliminates the white character correction effect and 2. ACL control: When the beam current volume is prevents side effects. high because the FBT load is not raised a certain 4. Black level correction ABL control: When the beam degree according to the beam current level, this current volume is high, this increases the black performs control so that the total load is fixed by level correction effect and prevents black fading. lowering the contrast using feedback control. When the beam current volume is low, this lowers the black level correction effect and prevents black fill in. The Fig. 5 is a block diagram of ABL voltage control.
Figure 5. ABL Voltage Control
ABL voltage
Voltage High
Voltage Low
0% 50% 100%
Input signal APL (%)
Figure 6. ABL Voltage Change Characteristics
-6- DX4P TG MPU Pin Location
Figure 7. MPU Pin Location
Note: Due to slight software upgrades, two different part numbers can be found on the DX4P family for the IC4002, MN102H75KTF and MN102H75KTL.
DX4P TG -7- MPU Pin Description Table PIN NUMBER TYPE CONTROL FUNCTION DESCRIPTION 2 INPUT /VSYNC Main Picture Vertical Synchrony 5 INPUT /RST Reset 7 INPUT /TEST Test Pin 12 INPUT /HSYNC Main Picture Horizontal Sync 20 INPUT VCOI Internal VCO input (external LPF input) 28 INPUT VREF DAC Reference Voltage Connection 30 INPUT IREF Resistance connecion for DAC bias current setting 31 INPUT COMP DAC phase compensator connection 33 INPUT CLL Clamp Level Low Input 34 INPUT VREFLS CCd reference voltage input 35 INPUT CVBS1 Composite video signal input 1 38 INPUT CVBS0 Composite video signal input 2 39 INPUT VREFHS CCd reference voltage input 40 INPUT CLH Clamp Level High Input 56 INPUT HHS_DET HHS Level Detector 57 INPUT SOS Voltage from each protector circuit 61 INPUT AFC2 Automatic Frequency Control from Tuner 2 62 INPUT ACL1 64 INPUT ACL2 65 INPUT AFC1 Automatic Frequency Control from Tuner 1 66 INPUT KEYSCAN2 Key Scanning (action,shutdown) 67 INPUT KEYSCAN1 Key Scanning (power,ch,vol.) 68 INPUT WP 69 INPUT SOS_2 Voltage from each protector circuit 72 INPUT RMIN Remote Control Input 76 INPUT OSC1 Clock Pulse Signal 79 INPUT FA PORT Service Mode Input PIN NUMBER TYPE CONTROL FUNCTION DESCRIPTION 1 OUTPUT MOMENT_B_DOWN Momentary Power Down 6 OUTPUT HFR Horizontal Freq.Reference 8 OUTPUT YS Video Signal Out 10 OUTPUT SYSCLK System Clock Output 15 OUTPUT VIDEO-MUTE Video Mute 17 OUTPUT WP 21 OUTPUT PDO Internal phase compare output (external LPF out). 23 OUTPUT YM 24 OUTPUT OSD_B Blue OSD 25 OUTPUT AUDIO-MUTE Audio Mute 26 OUTPUT OSD_G Green OSD 27 OUTPUT OSD_R Red OSD 29 OUTPUT LED SOS Led signal 42 OUTPUT HD/SD SW 1080i/480p switch 43 OUTPUT SERVICE SW Service Switch 44 OUTPUT AUDIO MUTE Mutes audio whe amp is used 45 OUTPUT AC_SW A.C. switch 46 OUTPUT SBD1 Serial interface 47 OUTPUT SBT1 Serial clock signal 48 OUTPUT ROTATION Landing Corr.Circuit 49 OUTPUT H_POSITION H-Raster position circuit 50 OUTPUT V_POSITION V-Center circuit 51 OUTPUT MOIRE_GAIN Tilt Correction circuit 52 OUTPUT HHS_REF HHS circuit 55 OUTPUT DEG_SW Activates Degauss relay 60 OUTPUT HDMIINT High Definition Miltimedia Interface 70 OUTPUT SCL1 I2C Bus Serial Clock 1 73 OUTPUT LPF_SEL Low Pass Filter Selector
-8- DX4P TG 75 OUTPUT OSC2 Clock Pulse Signal 78 OUTPUT SCL0 I2C Bus Serial Clock 0 81 OUTPUT 140V_SW +B On-Off PIN NUMBER TYPE CONTROL FUNCTION DESCRIPTION 71 I/O SDA1 I2C Serial Data Bus 1 80 I/O SDA0 I2C Serial Data Bus 0
