Analog Waveform Monitors

Features & Benefits

• Composite or Component Waveform Monitoring
• Composite Vector Display
• Picture Display
• Stereo Audio Display
• Time Code Phasing and Amplitude
• SCH and Color Framing Display
• Component Vector, Lightning, Diamond, and Bowtie

Applications

• Analog Baseband Video Monitoring for Broadcast and Postproduction Applications

The 1740A/1750A/1760 Series make up a family of analog video waveform/vector monitors with progressive features in support of today's demanding television environment.

Each model in the series provides improved video performance and ease of operation and incorporates application-specific features. The family includes the 1740A Series composite analog waveform/vector monitors, the 1750A Series, which adds SCH and color frame verification capabilities, and the 1760 Series for mixed-format component/composite applications. (While the 1740A and 1750A do provide basic component waveform monitoring capabilities with parade and overlay displays, only the 1760 provides full component monitoring capabilities.)

Each series includes models for NTSC, PAL, or dual-standard NTSC/PAL operation. For NTSC models, the last digit of the model number is '0' (1740A, 1750A, or 1760); '1' for PAL (1741A, 1751A, or 1761); and '5' for dual-standard NTSC/PAL (1745A, 1755A, or 1765).

The family features a common, straightforward operator interface, allowing the operator to take immediate advantage of the instrument's extensive feature set. Each operating mode provides a full set of operating controls, clearly labeled and within easy reach. Key controls are always available, with bezel buttons and knobs identified by intuitive on-screen labels.

Selection Guide

All family members provide the following standard features:

Eight Video Inputs eliminate the requirement for external input selectors, reducing total system cost in many applications. Since all eight inputs are connected directly to the instrument, signals may be paraded, overlaid, or displayed in comparison modes not normally available with a simple external switcher.

Waveform monitoring is analog for maximum waveform fidelity. There is no digital processing of the displayed signal. The selected input may be displayed in one- or two-line or one- or two-field sweeps on a continuous basis or identified lines of any field may be selected and displayed. Multiple inputs may be displayed at the same time or multiple filters may be applied to one input for signal analysis. Time and voltage cursors may be activated and positioned for reference or measurement.

Composite Vectorscope functions demodulate and display the color components of the NTSC or PAL signal. A microprocessor-controlled phase shifter provides accurate vector positioning and eliminates readjustment when switching between internal and external reference modes. Phase and amplitude cursors with on-screen readout allow system setup to reproduce specific chroma values and specific colors when luminance is similarly set using the waveform-display voltage cursors.

A Picture Monitor mode is provided for easy signal identification. This is particularly useful when the instrument is used to monitor many sources, as in a production suite or outside production vehicle. In waveform or vector line select mode, a line bright-up marker in the picture display identifies the selected line.

Stereo Audio Amplitude and Phase are monitored using a calibrated L/R Lissajous display. The operator can quickly see that the program audio will be properly reproduced on both monaural and stereo receivers. Correct phasing between two audio channels is quickly verified by the direction of the display; signal level (left + right) is confirmed relative to the CRT graticule; and stereo separation (left - right) is displayed in quadrature to the level display.

Audio frequency -3 dB bandwidth is 200 kHz. Phase match between the left and right channels is better than 1 degree at 20 kHz. Input is high-impedance bridging, either balanced or unbalanced, to allow signal monitoring of existing audio circuits.

This display of stereo audio is intuitive and easy to use and has gained wide acceptance in new-generation Tektronix vectorscopes.

Longitudinal Time Code is monitored in a frame rate display to allow observation of amplitude, synchronization, and phase with respect to reference vertical. Synchronization is confirmed by the stationary display and time code phase is easily determined by horizontal position of the time code sync word on the CRT.

These monitors provide multiple display modes, allowing simultaneous observation of the many important parameters that make up a television signal. For example, vector, waveform, and audio may be displayed together for an indication of signal quality without operator intervention.

In the 1750A, or 1760 with the SCH option, Subcarrier/Horizontal Phase and Color Framing are displayed graphically in the patented Tektronix polar SCH display. Sync jitter over the field is displayed as a moving sync vector dot or displayed as a timing error at a vertical rate to identify the relationship over the field time. Correct color framing is quickly verified by the position of the single sync vector dot relative to the color subcarrier vector when the monitor is externally referenced.

The SCH phase of the reference signal is separately sensed to allow reliable SCH and color framing comparison. Using this method of determining relative SCH phase and color framing eliminates the requirement for a precise horizontal timing match between the reference and measured signals and an external color-field identification input is not required.

User Interface

Characteristic of current-generation Tektronix instruments, an intuitive operator interface allows full instrument utilization with minimal reference to the provided user and maintenance manuals. Operating modes, any of eight video inputs, and key control knobs and buttons are always available for direct access from the front panel.

To keep operation easy and straightforward, the 1740A, 1750A, and 1760 family "learns" the user's preferences for waveform, vector, and picture modes (and SCH in the 1750A and 1760 with the SCH option). Returning to one of these modes restores the previous configuration. Changes to a mode configuration are easily made using front-panel buttons, supplemented by screen-labeled buttons and knobs. Knob operations such as position, gain, phase, etc., are stored as well.

The 1740A/1750A/1760 family is easily configured for special monitoring applications, which may be stored in user presets for easy recall. For example, a program line or off-air VITS may be set up as preset number 3. Preset number 3 could be named and later recalled to display line 19 of the selected input in 2H sweep, with voltage cursors marking proper signal levels. Other presets could be used to immediately access and display signals from other points in the system. Different operators could quickly return to preferred monitoring setups after specialized signal checks.

With eight loopthrough video inputs, the 1740A/1750A/1760 family is a versatile central point system monitor. This capability is particularly useful in the production studio, where several machines, cameras, and composite input/output feeds are in use.

As a machine monitor, the instrument may be operated from a central control panel, with waveform, vector (SCH and color framing with the 1750A Series and 1760 Series with SCH), audio, time code, and servo signals easily observed.

High-performance Design

The control system, based on Motorola's rugged MC68332 32 bit microprocessor with internal co-processing, facilitates instrument control and timing functions. Flash EPROMs simplify updating the instrument to the latest firmware configuration.

The 1740A/1750A/1760 family is based on completely new, high-performance analog video system electronics. Application Specific Integrated Circuits (ASICs), developed by Tektronix specifically to maintain signal fidelity in a television test instrument, handle internal signal routing and amplification. Video performance is tightly controlled providing confidence that the signal display accurately represents the signal under test.

As an example of this new video performance level, the series permits observation of the video signal at up to x10 vertical and x25 horizontal magnification. Any part of the signal may be positioned on-screen in any magnification. Overscan performance at any gain setting is virtually distortion-free.

DC Offset (position match) between two or more displayed channels is within 1 IRE or 7 mV. Loopthrough return loss is better than 40 dB to 10 MHz.

Operational Flexibility

Eight loopthrough video inputs may be connected to the rear panel of the 1740A/1750A/1760 Series, eliminating the need for a dedicated routing switcher bus in many applications. Any of these inputs may be selected singly or in combination from the front panel or through the RS-232 interface. Input selection may also be included in preset configurations recalled using a remote control connector.

A separate external input may be selected to synchronize the display, allowing relative SCH and color framing comparison between two input signals or with the house reference. Because a separate SCH evaluation is done on the reference signal, SCH and color framing displays are accurate over a wide input range.

Signal standards can be automatically selected, NTSC 525/60 or PAL 625/50, in dual-standard 1745A/1755A/1765 models. A CRT graticule suitable for both standards is provided. A microprocessor-controlled phase shifter may be activated to rotate the vector display to the correct position on the display. Once set for each standard, the instrument displays the correct vector rotation when the video standard is changed.

A new universal input power supply is a part of these monitors. AC mains in the range of 90 to 250 V, 50 or 60 Hz, are accommodated automatically. This new power supply will also operate from a nonsinusoidial supply, allowing battery operation using an external, high-efficiency switching inverter. A snap-lock power cord appropriate to the country of use is supplied with each instrument.