infernosoft : community : Tektronix 1410
This document describes operation of the Tektronix 1410 Video Test Signal generator. I first came across this test pattern generator where I used to work, where I planned to use it to make test videos for a handheld video video digitizer and playback device. I did not have the benefit of the original Tektronix factory manual and none was available on the web, so I systematically investigated what the buttons do and wrote up this document.
Some of the functions are mysterious to me: video synchronization and some finer points of NTSC color signals. I may add to this manual when I know more about those things and how to get the unit to create appropriate test signals.
Some of the test patterns are accompanied with oscilloscope traces of one or two scan lines. How I made them.
The 1410 consists of six modules, each of which provides a type of video test signal or provides some video switching function. Each module's signal can be individually accessed at one of the numbered Module Outputs jacks on the back of the signal generator.
At 114.5 VAC, the unit consumes 108 watts. (Meausred with a P4400 Kill A Watt.)
The Sync Generator module produces the basic horizontal and vertical synchronization pulses that frame the actual video signal. Without these pulses, the system that receives the signal has nothing to tell it when the video frames and lines begin.
There are plugs on the back for extracting the vertical and horizontal sync pulses. These are useful for such things as looking at individual scan lines with an oscilloscope.
In general, set INTERNAL: in so the green LED comes on.
The Color Bars module produces signals useful in diagnosing and calibrating a color video display system. The patterns generated are of well-known specific color values. When a display is set to show these colors correctly, one can assume that its color rendition is as good as it can be.
The switches in the right column select a particular type of color bar. Select from SMPTE, EIA, Full Field, /Y Ref, /Red, /Reverse.
Each switch in the left column subtracts some component of the color test signal. Select from Y, B-Y, R-Y, BURST, SYNC. In general, leave these in the ON position.
The bottom four switches affect the color subcarrier: SETUP, PHASE, AMPL, WHITE REF. PHASE shifts the phase of the color signal by 90°, resulting a change in all the isplayed colors. AMPL reduces the brightness of the color bars to 75%. When AMPL is at 75% (in), the WHITE REF switch can force the white bar to be fully white (in). In general, leave these in the out position.
To see Color Bar patterns, connect to J3 in the back of the unit and set SWITCHER to B with CONV BORDER Off. To access the Color Bar generator output directly, connect to J2 in the back of the unit.
This table shows what the various color test patterns look like. I have not calibrated the video digitizer and the images are JPEG, so these images are not test-pattern quality.
| DISPLAY | Image |
| SMPTE |  |
| EIA |  |
| FULL FIELD |  |
| /Y REF |  |
| /RED |  |
| /REVERSE |  |
| Component | Resulting Color Bars |
| Y (off) |  |
| B-Y (off) |  |
| R-Y (off) |  |
| BURST (off) |  |
| SYNC (off) |  |
AMPL 75% WHITE REF 75% |
 |
AMPL 75% WHITE REF 100% |
 |
| PHASE (R-Y) ALT |  |
The Switcher module has two functions. The "Switcher" part displays bits and pieces from each of the other test-pattern generator modules in six different ways. The "Convergence" part creates test patterns that show whether a video display system's geometry is set up correctly.
To access the Switcher output, connect to J3 in the back of the unit.
CONV KEY switches the convergence pattern on and off.
MATRIX combines outputs from the other modules. The switches in the left column gray area select which of the other signal generators' signals are superimposed on the convergence signal.
When MATRIX is out, the output is from the selected module. The correspondence between switches and modules is as follows:
| MATRIX Out | Signal Source |
| A | Synch |
| B | Color Bars |
| C | Convergence |
| D | Linearity |
| E | Pulse & Bars |
| F | Multiburst |
Samples of test patterns from each of these modules are illustrated in their corresponding sections of this document.
When Matrix is in, the screen is divided into horizontal slices; each slice displays the signal from a specific pattern generator. The lettered switches let you select a mode; each mode is a specific set of video signals.
This table shows for each mode which row contains which test pattern type. The actual image would depend on what pattern each of the modules was generating. For these pictures, each module was set to a representative configuration. The Color Bar generator was set to /REVERSE, so when color bars appear in the middle row, it looks like two rows but is counted as one.
| MATRIX In | Image |
A 7 rows: Color Bars, Linearity, Pulse & Bars, Synch, Multiburst, Linearity, Color Bars |
 |
B 7 rows: Synch, Multiburst, Linearity, Color Bars, Pulse & Bars, Multiburst, Color Bars |
 |
C 3 rows: Synch, Color Bars, Linearity |
 |
D 3 rows: Linearity, Multiburst, Color Bars |
 |
E 3 rows: Pulse & Bars, Color Bars, Multiburst |
 |
F 3 rows: Pulse & Bars, Multiburst, Linearity |
 |
CONV BORDER turns on or off an area on the outside margins of the screen to contain the convergence pattern.
| CONV BORDER |  |
The controls in the right column affect the convergence signal that this module creates.
The VERTIVCAL POSITION knob moves the pattern up (ccw) or down (cw). The HORIZ POSITION knob moves the pattern left (ccw) or left (cw). Dots turns dots on or off.
VERT LINES turns vertical lines on or off. HORIZ LINES turns horizontal lines on or off. In general, press all three buttons in.To see Convergence patterns, set MATRIX to off (out) and select C (convergence pattern). Press CONV KEY in for small boxes or out for large boxes.
| CONV KEY | Image |
| out |  |
| in |  |
The Linearity module creates test patterns useful for calibrating the brightness levels of a video display. The module can create signals in two basic modes, FLAT FIELD or LINEARITY. The FLAT FIELD test images are basically all one brightness level; the Linearity test images are gradients from black to white.
To see LINEARITY patterns, connect to J3 in the back of the unit and set SWITCHER to D with CONV BORDER Off. To access the Linearity pattern generator output directly, connect to J4 in the back of the unit.
Three buttons select the ramp signal in 5 steps, 10 steps, or a smooth ramp.
The color subcarrier can be turned on or off, optionally adding a yellow tint.
When it is on, it can be set to full or partial intensity. To select a ramp signal, set the knob to point down to the Linearity section.The knob selects video levels in eleven steps of 10% from 0% to 100% brightness.
Three buttons select adidtional features in the Flat Feild mode. FULL FIELD means the stripes are off.
/ALT LINEARITY means the stripes are controlled by the right Linearity section.
/ALT 90° SUBC means the stripes are at a steady level, but their color information is controlled by the two buttons below.
In the following example images, the left column shows the position of the IRE LEVEL knob; the middle column shows the setting of the LINEARITY switches, and the right column shows the resulting images. The 5-10-R sequence is arbitrary. If the FLAT FIELD switches were set to FULL FIELD, there would be no horizontal lines across the image.
| IRE LEVEL | LINEARITY | Image |
| 0 | 5 |  |
| 10 | 10 |  |
| 20 | Ramp |  |
| 30 | 5 |  |
| 40 | 10 |  |
| 50 | Ramp |  |
| 60 | 5 |  |
| 70 | 10 |  |
| 80 | Ramp |  |
| 90 | 5 |  |
| 100 | 10 |  |
| 0 | Ramp |  |
Linearity (Oscilloscope trace of 2 scan lines shown for comparison.) |
5 |
|
Linearity (Oscilloscope trace of 2 scan lines shown for comparison.) |
10 |
|
Linearity (Oscilloscope trace of 2 scan lines shown for comparison.) |
Ramp |
|
The function of the Subcarrier switches is mysterious to me.
The Pulse & Bar section creates signals sueful for analyzing a receiver's response to high-frequency signal pulses. The visual patterns should show crisp lines, not smears.
Burst turns on or off the colorburst signal. It should be on if color images are to be displayed. Overlay In means that both bars and pulses are shown.
Window confines the vertical bar to a square area in the middle of the screen or allows the bar to occupy the full height of the screen.
Bar This one's complicated; I'll fill in more here later.To see Pulse & Bar patterns, connect to J3 in the back of the unit and set Switcher to E with Conv Border Off. To access the Linearity pattern generator output directly, connect to J5 in the back of the unit.
For basic functionality, set it up like this:
Pulse & Bar: Overlay off. Amp full (in). Luminance in. Pedestal/Setup/Off to Pedestal. Window off. Field sq. wave off. Burst On. Pulse: 2T-T-T/2 to 2T Mod On. Bar: 2T-T-t/2/Mod to T. (Oscilloscope trace of 1 scan line shown for comparison.) |
|
The Multiburst module creates video signals that are useful to measure a video display system's resolution. The patterns are created by chnaging the frequency of the brightness level in the video signal.
To see Pulse & Bar patterns, connect to J3 in the back of the unit and set Switcher to E with Conv Border Off. To access the Linearity pattern generator output directly, connect to J6 in the back of the unit.
Start with the Multi-Burst/Sweep/Manual group. Multi-Burst creates seven vertical bars across the screen which alternate black and white at ever-increasing frequency. The Freq Range (High/Low) button selects the starting frequency.
When Sweep is selected, the signal is of a single frequency for every horizontal line, increasing downwards.
When Manual is selected, the frequency of the signal is set by the bigFrequency knob and is the same for every horizontal line. When Freq Range is set to Low, the frequency can be set between 100 kHz and 6 MHz; when it is set to High, the range is 330 kHz to 20 MHz.
Markers turns on and off horizontal lines in the display. The markers divide the screen into four zones with gray, white, black, and gray lines.
Composite/Continuous switches between it generating a coherent TV signal and just sweeping the output signal. This will only generate visible images in the Composite mode.
Amplitude sets the amplitude between full and 50%.
Burst turns on and off the colorburst signal.
| Settings | Image |
Multi-Burst Low (Oscilloscope trace of 1 scan line shown for comparison.) Note: The Moiré pattern in this image is caused by the video digitizer. |
|
Multi-Burst High (Oscilloscope trace of 1 scan line shown for comparison.) Note: The Moiré pattern in this image is caused by the video digitizer. |
|
Sweep Low Note: The Moiré pattern in this image is caused by the video digitizer. |
 |
Sweep High Note: The Moiré pattern in this image is caused by the video digitizer. |
 |
Manual Low 100kHz (Oscilloscope trace of 1 scan line shown for comparison.) |
|
| Manual Low 3rd tick |  |
| Manual High 330kHz |  |
| Manual Low 100kHz, Markers, Reduced |  |
