Pattern Generator

Experimental Purposes

1 Getting to know the basic Pattern in the pattern generator.

2 Measuring standard composite video and Voltage on each Pattern.

3 Measuring the modulated wave on the video modulator.

4 Measuring IF video.

Circuit diagram

Tools and materials in used

A Pattern Generator signal TV, LODESTAR CPG-136 74

An Oscilloscope 40 MHz

A Passive Probe

A Power Supply

A BNC to BNC 75Ω cable

A BNC to RCA 75Ω

A T connector

Experimental Procedure

1. Set-up equipment look like in the circuit diagram
2. Connect the Pattern Generator with power source 8, 5 V, and then push ON the instrument.
3. Pattern generator output switches on and observe put on VIDEO waveforms for each pattern.
4. Observe and picture synchronizing signal and horizontal blanking, vertical blanking, front and rear porch, and image information of each pattern
5. Images and specify voltage waveforms.
6. Pattern generator output switches on and observe put in the IF waveform for each pattern and frequency measurement.
7. Image of the wave form and specify voltage.
8. Image signal for one frame (still image) in composite video, determine the level and period.

Basic Theory

A Pattern Generator or Generator Digital Pattern is an electronic testing equipment or software used to generate the stimulation of a digital electronics. Digital electronic stimulation of certain types of electrical wave form varies between two voltages that match the conventional two-logic ('logic low' and 'logic high' or '0 'and the '1'). The main purpose of the digital pattern generator is to stimulate the input of digital electronic devices. A digital pattern generator is a synchronous digital stimulus sources, a pulse generator has the objective to generate electrical pulses of various shapes, they are mostly used for testing in the field of electric or analog.

Various kinds of image patterns in the Pattern Generator are as follows:

a. Dot

To check and adjust the static convergence in the middle of the screen with a low brightness. This should be done according to the television manufacturer's instructions.

b. Crosshatch

Plaid pattern with horizontal lines and vertical lines with the background color of black and white color line.

1) To check and adjust the horizontal and vertical dynamic convergence and the convergence angle.

2) By linearity of deflection the correct horizontal and vertical, horizontal white lines should be a rectangular equilateral.

If this line is not sharp and visible lower intensity than the horizontal line, the amplitude response is possible recipients will not be enough.

c. White

This pattern contains a signal 100% white (without color information) with alternating burst.

1. Images for constant brightness on the entire screen

2. Color picture tube for setting a good white

3. Limitation of fire flow on the color picture tube.

4. For the video recorder is ideal pattern for the current settings. It can also to set the FM demodulator (setting white level).

d. Color

Color beam consists of 8 vertical color bar standard and a reference beam horizontally. Beams 8 colors are arranged in order of depreciation luminance. From left to right beams D color is white, yellow, cyan, green, magenta, red, blue, and black. This pattern is used to set the operational control of the receiver at the correct position. Horizontal beam (white level) on the bottom of this pattern is used as a standard when set the amplitude of color differences in correlation with luminance signal in the picture tube. Signals can be used for resetting the signal amplitude of the demodulator circuit and the matrix, as the output can be compared with the reference beam. In addition to the above purposes, this pattern can be used to check the overall color appearance. So can also be used checks and settings on the receiver or VCR:

1. Lock Inspection burst.

2. AGC examination of color and which create the color.

3. Examination series reactance of the subcarrier regenerator.

4. Examination of the regenerator subcarrier synchronization.

5. Checking circuit identifier (identification) PAL.

Signal Synchronization

Synchronization signal is a signal that is always given periodically and remains, serves to drive a raster scanning path in every television set so that the formation of the video signal into an image and the exact arrangement will remain the same as the original position in the field of raste camera (picture production), therefore the synchronization signal is always supplied along with the video signal sent anywhere. For the formation of this raster scanning system will require two kinds of synchronization are:

- Namely the horizontal synchronization signal to the horizontal scanning provided at each horizontal retrace.

- Vertical sync signal is for vertical scanning provided on each vertical retrace.

Video signal which is equipped with synchronization signals called the complete video signal (Composite Video signal / CVSl), while for color video signal is called Color Composite Video Signal (CCVS). Because the video signal has been added color information signals, i.e. signals and signal Burst Color Sub Carrier.

Result

CONCLUSION
1. Voltage at all about the same video system.
2. At the time of the IF mode is turned down because the amplitude of the voltage will also be down
3. IF output frequency is also almost the same because there is no significant difference in amplitude.
4. Tension on the composite video is lower than the voltage on any other video system