TEK TPG20 Test Pattern Generator

Features

The continual evolution of broadcast standards and formats has brought with it a need for more versatile test signal generation. Today's applications demand generators which can switch instantly between component and composite, digital and analog and even between aspect ratios to accommodate the newer extended definition widescreen formats.

The TPG20 from Tektronix answers these needs, and more.

This powerful and flexible multi-standard, multi-format unit provides a comprehensive range of precise, digitally synthesized, still and moving patterns. The result is a highly functional tool suitable for all environments where test signals, patterns, and images are required.

The TPG20 contains over 70 different line based test signals in a variety of formats. In addition, frame based patterns with controllable moving content are available in the PAL and NTSC formats. This combination of test signals and patterns provides tools for both objective and subjective testing of equipment and systems.

In addition to the resident test signal complement, a library of patterns and images is provided with the TPG20. These may be downloaded into the TPG20 with a DOS compatible personal computer. Custom images such as logos and station ID's may be created from user supplied D1 videotape or from computer graphics files supplied on floppy disk.

The TPG20 operates in either 525 or 625 line standards. Composite formats supported include NTSC, PAL, and SECAM. Component formats include YPBPR, GBR, and YC. Analog, parallel digital, and serial digital outputs are provided.

Simultaneous output of digital and equivalent analog formats is available in either of the selected output line standards. If composite digital is selected, then the analog output is composite. If component digital is selected, then analog component is present.

The TPG20 can also be made available in PAL-M and PAL-N to provide either PAL, PAL-M, PAL-N, CCIR 656 or NTSC, PAL-M, PAL-N, CCIR 656 configurations.

The TPG20's clearly labeled front panel, logically placed controls, and LED display provide highly functional yet simple operation. Function and pattern selection is accomplished with push buttons and the control knob. Parallel levels of various functions are obtained with successive pushes of the button. Options for each function level may be scrolled with the knob. Pressing the SELECT button completes the process.

All TPG20 patterns and images are generated using computer synthesis and prefiltering and encoding techniques to provide outputs that are digitally true and which exactly correspond to the theoretical characteristics of the signal.

To ensure the ultimate in analog output quality, the TPG 20 post-processes the digital outputs using a multi-tap over-sampling filter before D to A conversion. This avoids the need for sharp cutoff output filters which can cause ringing and other forms of signal degradation.

In accordance with PAL serial digital standards, the TPG20 employs subcarrier locked generation of PAL test signals and patterns. The TPG20 also uses the same luminance and chrominance envelope values for the active area of every line in the field. This method of signal generation provides signals suitable for most general applications and is fully compatible with the Tektronix VM 700A measurement routines. For waveform monitor measurements of pulse ringing and short time distortion, line select operation is required.

Allows the selection of the available output formats such as 625 GBR or 525 composite digital, and many more.

Where selection is made from the multitude available. Patterns are grouped in families to reduce confusion.

This useful feature allows the user to trigger externally a non-TV oscilloscope on any line in a frame - and get the number right in any standard.

The TPG20 digital outputs are absolute, however the analog outputs may be trimmed using the Gain control. No guesswork is required - gain adjustment steps are in convenient engineering units.

The TPG20 has two frame buffers and this button toggles between them. Newly selected patterns are first loaded into the buffer not being displayed and the buffer is then switched. The user may then toggle between the two most recently used patterns.

Some of the TPG20 patterns contain special moving segments. This button parades through Style, Speed and Pause menus. Style selects circular or various linear motion. Speed is defined in pixels per frame and Pause controls the wait time at the end of travel before movement restarts.

Three levels of menu allow the adjustment of output H-Phase, VPhase and Subcarrier Phase with respect to the Reference input.

Turns the "Genlock to Reference" input on and off. The reference must be the same line standard as the output being generated or it will be ignored.

Nine different overall settings of the TPG20 can be retrieved using the alternative front panel button numbers 1 to 9. They are recalled by simply pressing the Memory button and then choosing the required number. To store a setting: set up the TPG20 as needed, press Memory and then hold the number button until the button LED extinguishes.

Sets up the TPG20 for different system variables such as the types of crystal oscillator present, calibrated gain setting and so on.

• Multiformat Test Signal Pattern, and Image Generator
• Serial and Parallel Composite and Component Digital Outputs
• Analog Composite, Y/C, Y and Color Difference and GBR and Sync Output
• 10-Bit Resolution on Three Independent Channels
• Instant Switching Between Any Two Patterns
• Controllable Moving Patterns
• Fully Genlockable
• Supports VM700A Measurement Routines
• Conforms to Digital Standards CCIR 601, 656: EBU Tech 3267, SMPTE 125M, 244M, 259M, 267M
• Compatible with 16:9 EDTV Standards
• Unlimited Pattern Complexity
• Pattern Upgrades Available

Specifications

Note that the BNC connectors are multifunction and may be used for more than one output format.

Composite and Y/C - Dual output 1 V_p-p into 75 Ohm, BNC connectors.

GBR - 0.7 V_p-p video into 75 Ohm, and
0.3 V_p-p syncs (for those signals with syncs), BNC connectors.

Component - Y P_B P_R; Betacam, MII, and EBU N10 levels into 75 Ohm, BNC connectors.

Trigger - 0.5 V into 75 Ohm (negative going from 0 V) with a duration of one line programmable to any line in color frame.

Digital (Composite NTSC and PAL and Component CCIR 656) - Parallel and serial.

Parallel - One output via DB 25 connector.

Serial - Two outputs into 75 Ohm, BNC connectors.

Output Bandwidth - ±0.1 dB to 6.5 MHz; typically ±0.1dB to 8 MHz.

Amplitude Error - <1%.

Non-linearity*¹ - <1%.

Differential Gain*² - 0.75%.

Differential Phase*² - <0.5°.

Output Return Loss - >36 dB at 4.5 MHz.

Gain Adjustment - Variable +3 dB to -20 dB.

Reference - Black burst or composite video, loop through 75 Ohm BNC connectors.

Input Return Loss - >36 dB at 4.5 MHz.

Signal Level - 0.3 V ±6 dB sync and burst.

Data Input - 25-Pin parallel (Centronics compatible).

Control - RS-232.

*¹ Measured with a VM 700A using a 5 step staircase.

*² Measured with a VM 700A modulated ramp.

Voltage Range - 98 to 270 V AC, 50/60 Hz, IEC fused socket (5 A).

Consumption - 65 VA maximum.

Temperature -
Operating: 0 to +40°C.
Nonoperating: -30 to +75°C.