Color-tv-crosshatch-generator
This circuit serves as a simple, low-cost crosshatch generator for convergence and geometry adjustments in color televisions. It is driven by two clock signals, one for horizontal drive (IC1ab) and another for vertical drive (IC2ab). The outputs from these clocks are sent to two binary counters within IC5, which generate line and field sync pulses along with their respective blanking periods. The line clock pulses, buffered through IC1c, are differentiated using the components C3 and R5 to create vertical bars. These bars are controlled by IC4a, which suppresses them during the line blanking period, determined by the coincidence of outputs Q3 and Q4 from IC5a, and detected by IC4b. The output from IC4b is also differentiated using C5 and R7 to generate the line sync pulse (LS). A similar method is employed to create horizontal lines and the field sync pulse (FS), where the count of IC5b is reset at 12 upon the coincidence of Q3 and Q4. The Q2 and Q4 coincidence is used to generate the sync pulse FS and the corresponding blanking period. The line and field sync pulses, LS and FS, are then combined in IC4d.
The crosshatch generator circuit is designed for use in color television systems, where precise adjustments to convergence and geometry are essential for optimal image quality. The circuit utilizes two clock signals that provide the necessary timing for horizontal and vertical synchronization. The horizontal clock signal, generated by IC1ab, is essential for driving the horizontal components of the display, while the vertical clock signal from IC2ab ensures proper vertical alignment.
The binary counters within IC5 are critical for producing sync pulses that dictate the timing of the displayed image. The line and field sync pulses are essential for maintaining the correct frame rate and ensuring that the image is stable. The differentiation process implemented by C3 and R5 effectively transforms the buffered line clock pulses into distinct vertical bars, which are visually represented on the screen.
IC4a plays a vital role in controlling the visibility of these vertical bars, ensuring that they are not displayed during the line blanking period. This is crucial for maintaining a clean and flicker-free image. The detection of the coincidence between Q3 and Q4 outputs of IC5a, as processed by IC4b, ensures that the vertical bars are only visible when appropriate, enhancing the overall user experience.
The generation of the line sync pulse (LS) is achieved through further differentiation of the output from IC4b, allowing for precise timing control. The horizontal lines and field sync pulse (FS) are generated through a similar methodology, with the reset of IC5b at the count of 12 ensuring that the aspect ratio of the displayed image remains correct.
Finally, the combination of line and field sync pulses in IC4d is essential for coordinating the overall synchronization of the display, allowing for a coherent and stable visual output. The design of this circuit reflects a thoughtful approach to achieving low-cost solutions for high-quality image adjustments in color television systems.This circuit provides a simple, low-cost crosshatch generator tor convergence and geometry adJUStments on color TVs. The generator is driven by two clocks, one for the horizontal drive, IC1ab, and one for the vertical drive, IC2ab.
The clock outputs are applied to the two binary counters contained in IC5 which generate the line and field sync pulses and respective blanking periods. Line clock pulses, buffered by IC1c, are differentiated by C3/R5 to produce the vertical bars. These bars are gated by IC4a which suppresses the bars during the line blanking period produced by the coincidence of Q3, Q4 outputs of IC5a, detected by IC4b. This output is also differentiated by C5/R7 to produce the line sync pulse, LS. A similar process is used to generate horizontal lines and the field sync, except that in order to give the correct aspect ratio, the count of IC5b is reset at 12, coincidence of Q3 and Q4.
In coincidence of Q2, Q4 is used to generate the sync pulse FS and the blanking period. The line and field sync pulses, LS and FS, are combined in IC4d. 🔗 External reference
The crosshatch generator circuit is designed for use in color television systems, where precise adjustments to convergence and geometry are essential for optimal image quality. The circuit utilizes two clock signals that provide the necessary timing for horizontal and vertical synchronization. The horizontal clock signal, generated by IC1ab, is essential for driving the horizontal components of the display, while the vertical clock signal from IC2ab ensures proper vertical alignment.
The binary counters within IC5 are critical for producing sync pulses that dictate the timing of the displayed image. The line and field sync pulses are essential for maintaining the correct frame rate and ensuring that the image is stable. The differentiation process implemented by C3 and R5 effectively transforms the buffered line clock pulses into distinct vertical bars, which are visually represented on the screen.
IC4a plays a vital role in controlling the visibility of these vertical bars, ensuring that they are not displayed during the line blanking period. This is crucial for maintaining a clean and flicker-free image. The detection of the coincidence between Q3 and Q4 outputs of IC5a, as processed by IC4b, ensures that the vertical bars are only visible when appropriate, enhancing the overall user experience.
The generation of the line sync pulse (LS) is achieved through further differentiation of the output from IC4b, allowing for precise timing control. The horizontal lines and field sync pulse (FS) are generated through a similar methodology, with the reset of IC5b at the count of 12 ensuring that the aspect ratio of the displayed image remains correct.
Finally, the combination of line and field sync pulses in IC4d is essential for coordinating the overall synchronization of the display, allowing for a coherent and stable visual output. The design of this circuit reflects a thoughtful approach to achieving low-cost solutions for high-quality image adjustments in color television systems.This circuit provides a simple, low-cost crosshatch generator tor convergence and geometry adJUStments on color TVs. The generator is driven by two clocks, one for the horizontal drive, IC1ab, and one for the vertical drive, IC2ab.
The clock outputs are applied to the two binary counters contained in IC5 which generate the line and field sync pulses and respective blanking periods. Line clock pulses, buffered by IC1c, are differentiated by C3/R5 to produce the vertical bars. These bars are gated by IC4a which suppresses the bars during the line blanking period produced by the coincidence of Q3, Q4 outputs of IC5a, detected by IC4b. This output is also differentiated by C5/R7 to produce the line sync pulse, LS. A similar process is used to generate horizontal lines and the field sync, except that in order to give the correct aspect ratio, the count of IC5b is reset at 12, coincidence of Q3 and Q4.
In coincidence of Q2, Q4 is used to generate the sync pulse FS and the blanking period. The line and field sync pulses, LS and FS, are combined in IC4d. 🔗 External reference