Aim-TTi TGA1244 - 4 Channel, 15MHz, 40MS/s 64k Arbitrary Waveform Generator, RS232/GPIB

TGA1200 Series Universal ARB Waveform Generators

Universal Generators

The TGA1200 series combine a true variable clock arbitrary generator with a high performance DDS function generator and pulse generator in a single instrument.

A True Arbitrary Generator

The TGA1200 series are highly sophisticated 12-bit arbitrary generators capable of recreating virtually any waveform.

Variable Clock Architecture

True variable clock architecture is used with clock speeds between 0.1Hz and 100MHz (40MHz on TGA124x units). This architecture avoids the clock jitter associated with DDS arbitrary generators and permits waveform linking, looping and sequencing. (See page five for more about variable clock architecture).

Waveforms may be defined with up to 4096 vertical points and from 8 to 1M horizontal points (4 to 64K points on TGA124x units). Arbitrary waveforms may be replayed at a specified waveform frequency, period or sample rate. An external sample clock can also be used on TGA1210x units. On TGA124x units, up to 100 user-defined waveforms can be stored within the instrument’s non-volatile memory. On TGA1210x units waveform storage is on removable Compact Flash memory cards and is therefore effectively unlimited.

Function Generator

Each channel can operate as a full DDS function generator. High quality sine, cosine, haversine, havercosine and square waves are available between 1mHz and 16MHz (TGA124x) or 40MHz (TGA1210x).

Triangle, ramp and sine(x)/x waveforms are available from 0.1mHz up to 100kHz.

TGA1200 Series - Main Features

• 1, 2 or 4 waveform channels, independent or linked.
• 40MS/s or 100MS/s 12-bit arbitrary waveform capability using true variable clock architecture.
• 64K or 1M point waveform memory per channel.
• 16MHz or 40MHz function generators using DDS*.
• Multiple ‘standard’ waveforms including sine, square, triangle, haversine, ramp, pulse and sin(x)/x.
• Pulse train pattern generation for up to 10 pulses.
• Complex waveform sequencing and looping capability using up to 1024 waveform segments.
• Wide range sweep, AM, tone switching, signal summing. * DDS = direct digital synthesis
• Inter-channel triggering, summing and phase control.
• Multiple generators can be easily phase locked.
• External ARB clock input (TGA1210x units only).
• Waveform creation/editing tools built-in; sophisticated external Windows based software included.
• Built-in trigger generator, gated and triggered burst modes.
• Tone switching facilitates precision DTMF generation.
• Unlimited waveform storage using CF memory cards (TGA1210x units only).
• GPIB (IEEE-488.2), RS-232 and USB interfaces (TGA124x units have GPIB and RS-232 only).

40MS/s or 100MS/s - One, Two or Four Channels

Waveform Creation and Editing

Waveform creation and editing features are incorporated within the instrument. These include waveform insert, point edit, line draw, amplitude adjust and invert. A wide range of standard waveforms is available for insertion within an arbitrary waveform. Sections of existing arbitrary waveforms can also be inserted.

For more sophisticated waveform creation and editing, Waveform Manager Plus software for Windows is provided (see further on in this brochure for more detail). Waveforms created on a PC can be down loaded to the instrument via the digital interfaces (or memory card where fitted).

Memory Card Storage

TGA1210x units incorporate a Compact Flash memory card giving effectively unlimited storage for waveforms and set-ups. Waveform data can be transferred directly from a PC to the memory card using the USB card reader/writer supplied.

GPIB, RS-232, USB

The TGA1200 series incorporates both RS-232 and GPIB (IEEE-488) interfaces as standard. TGA1210x units also have a USB interface. These can be used for loading arbitrary waveforms and for remote control of all the instrument functions.

Generating More Voltage

For applications requiring more than 20V pk-pk emf, an external wideband amplifier is available. The WA301 can provide up to 30V pk-pk from 50 .

Wide Range Sweep

All waveforms can be swept over their full frequency range at a rate variable between milliseconds and minutes. Sweep can be linear or logarithmic, single or continuous. Single sweeps can be triggered from the front panel, the trigger input, or the digital interfaces.

Multiple channels can be swept simultaneously.

Built-in Trigger Generator

All waveforms are available as a triggered burst whereby each trigger edge will produce one burst of the carrier. Start and stop phase is fully variable. Both Triggered and Gated modes can be operated from the internal trigger generator, from an adjacent channel, an external source or a key press or remote command. The trigger generator signal is available as a separate output if required.

Tone Switching

The TGA1200 series can provide triggered switching between up to 16 frequencies of standard or arbitrary waveforms. Tone switching modes can be gated, triggered or FSK using any trigger source. By summing two channels together it is possible to generate precise DTMF test signals.

Fast and Easy to Use

All of the main information is clearly displayed on a backlit 80 character LCD. Eight 'soft' keys enable fast data editing. Parameters can be entered directly from the numeric keypad or changed with the spin wheel.

On the 2 and 4 channel models, a Copy Channel key enables similar setups to be created across multiple channels with ease.

Multi-Channel Summing

Waveform Summing sums the waveform from any channel into the next channel. Alternatively any number of channels can be summed with an external signal. This permits complex modulations to be created such as noise superimposition.

Inter-Channel Triggering and Modulation

Because any channel can be triggered by the previous or next channel, waveforms on different channels can be ‘daisy chained’ and looped. By summing the channel outputs, many segments from different channels can be used to generate the final waveform.

A channel can be used to AM modulate or SCM modulate another channel.

Digital Modulation

Inter-channel modulation and summing allows the simulation of various telecom digital modulation systems.

Waveform Manager Plus - Included with all TGA1200 Series Generators

Advanced Waveform Creation, Editing and Management Software

• Full waveform building tools including standard waveforms, mathematical expressions, and freehand drawing.
• Operates under Windows 95, 98, Millennium, NT, 2000 and XP.
• Supports vertical resolutions up to 16 bits (65536 points).
• Supports horizontal resolutions to over one million points.
• Provides waveform import and export via clipboard functions.
• Directly supports waveform upload from some Tektronix DSOs.
• Supports download and upload via RS-232, GPIB and USB.

Waveform Building Tools

Toolkit

Waveforms can be built in any number of sections using any combination of the following: Standard waveforms, mathematical expressions, drawn waveforms, uploaded waveforms, imported waveforms (using clipboard), existing stored waveforms. Note: Waveform section limits can be defined via moveable cursors which can be dragged or positioned numerically.

Standard Waveforms

The following waveforms are available directly from the Waveforms dialogue box: Sine, square, triangle, pulse, ramp, sinc [sin(x)/x], gaussian, exponent, noise. Note: The mathematical expression for any standard waveform can be examined by opening the expression editor window.

Expression Editor Functions

The following mathematical operators are available within the expression editor: Add, subtract, multiply, divide, x n , sin, cos, arcsin, arccos, abs, log 10 , log e , e n , square root, floor, ceiling, random, pulse, in conjunction with constants and waveforms. Note: The expressions used for each section of a waveform are retained and can be displayed in a drop-down window.

Expression Libraries

The mathematical expressions used for waveform creation can be stored in libraries. A default library is created for each project which includes a number of useful examples including waveshapes and modulations.

Waveform Drawing Functions

Waveforms can be created or edited using freehand drawing and/or point to point line drawing.

Smooth

Waveforms can be smoothed using a running average filter. Start and end points can be specified as well as the number of points to average.
 

Waveform Editing/Conversion

Toolkit

All of the waveform building tools previously mentioned can be used to edit existing waveforms. In addition waveforms can be manipulated directly using the following functions:

Resize Waveform

Allows a waveform to be resized horizontally to any length between 4 and 1M horizontal points.

Note: The vertical resolution of a waveform is automatically adjusted when it is downloaded to the generator. Thus an 8-bit waveform from a DSO will be expanded to 12-bits if it is downloaded to a 12-bit generator (and vice versa).

Waveform Mathematics

The Waveforms Maths function allows waveforms to be combined and manipulated independently of the expression editor. Waveforms can be scaled, offset, added, subtracted or multiplied using dialogue boxes.

Note: Waveforms can also be combined and manipulated within the expression editor giving access to the full range of mathematical functions.
 

Input/Output Functions

File Formats

Waveforms can be read from and saved as any of the following formats: WFM (binary), NRM (normalised data in ASCII), WAV (WaveCAD), ASC (WaveCAD), DSF (Tektronix DSO).

Waveform Download/Upload

Waveforms can be downloaded/uploaded to/from TTi arbitrary generators (or certain Tektronix DSOs) using either an RS232 or GPIB (IEEE-488) interface or, for the TGA1210x, a USB interface.

Clipboard Functions

Waveforms can be imported to the program and exported from the program using the Windows Clipboard.

Waveform import uses the "Text" clipboard format (i.e. numeric lists). This enables waveforms to be imported from spreadsheets such as Excel and from mathematical programs such as MathCad. Values are automatically normalized and re-scaled. Waveform export creates multiple clipboard formats of Text (normalized numeric values between ±1), Bitmap (as per on-screen display) and Picture (metafile retaining waveform vector properties). Note: Pictures or bitmaps can be pasted into programs such as Word for documentation purposes.

Display Area and Printing

Multiple waveform windows can be open simultaneously. Each window is fully scalable. Variable zoom is provided with panning from a "navigator" sub-window. Waveform section limits can be defined via moveable cursors which can be dragged or positioned numerically. Waveforms can be printed with automatic annotation and scaling.
 

Management and Utilities

Projects

To maintain good housekeeping, waveforms can be organised into "projects" with separate directory structures. Each project maintains its own library of expressions. Waveforms and expressions can be imported and exported from other projects.

Instrument Setup

The instrument setup screen enables options for the waveform generator to be set from the program. Examples of settable options are output amplitude, clock frequency and trigger source.

Help

Full on-screen Help is available with a hyper linked contents table.
 

Variable-clock ARB Architecture

Direct Replay for Jitter-free Waveforms

All TGA1200 series units generate arbitrary waveforms using a variable clock architecture rather than DDS. This ensures that every point in the waveform is replayed exactly as it was defined, the rate of replay being set by the clock frequency. By contrast, a DDS arbitrary generator uses a fixed clock frequency and varies the replay rate by duplicating or omitting waveform points. Unless there is an integer relationship between the desired replay rate, clock frequency and waveform length, each "cycle" of the waveform will differ from the previous one, resulting in jitter.

Sequencing for Increased Waveform Length

Variable clock architecture also allows sequencing and looping. The 64K words of waveform memory per channel provided in TGA124X units can be used to create arbitrary waveforms with many more than 65536 points.

Many real-world waveforms include repetitive elements. By using a segment of the memory to recreate each repeating element, the waveform can be constructed by a "sequence" in which the individual elements are replayed in a defined order and with a defined number of repetitions (loop count). In this way waveforms can be created with a much greater number of points than the waveform memory size.

DDS arbitrary generators can not do this and the effective waveform length is limited to the actual waveform memory size.