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Tel: +441732355993
  • A precision DDS function generator module with 0.001Hz to 10MHz frequency range, 6 digits or 1mHz resolution, and 1ppm stability and 10ppm one year accuracy . The 7028 is simple operation and features AM, FSK, gated and tone switching modes.

    Features

    High measurement accuracy
    DDS (direct digital synthesis) is a technique for generating waveforms digitally using a phase accumulator, a look-up table and a DAC. The accuracy and stability of the resulting waveforms is related to that of the crystal master clock. When correctly engineered, the DDS generator offers not only exceptional accuracy and stability but also high spectral purity, low phase noise and excellent frequency agility.

    Wide frequency & amplitude range
    The 7028 can generate waveforms between 0.001Hz and 10MHz with a resolution of six digits and a one year accuracy better than 10ppm. Amplitude is variable between 5mV and 20V pk-pk from a source impedance of 50 Ohm or 600 Ohm. Waveform quality remains excellent over the full amplitude range.

    Easy and convenient to use
    The 7028 is particularly easy to use. All of the main information is clearly displayed on a backlit LCD with 4 rows of 20 characters. Sub menus are used for the modulation modes and other complex functions. All parameters can be entered directly from the numeric keypad. Alternatively most parameters can be incremented or decremented using the rotary encoder for quasi-analogue control.

    Sweep
    All waveforms can be swept over their full frequency range (0.1Hz minimum) at a rate variable between 20 milliseconds and 15 minutes. The sweep is fully phase continuous. 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. A sweep marker is provided that is adjustable whilst sweep is running. The markers can provide a visual indication of frequency points on a 'scope or chart recorder.

    Gated
    The Gated mode turns the output signal On when the gating signal is high and Off when it is low. The gating source can be the front panel key, trigger input socket, or bus interface signal.

    AM
    External Amplitude Modulation is available for all waveforms via the VCA input.

    FSK
    Frequency Shift Keying provides phase coherent switching between two selected frequencies at a rate defined by the switching signal source. The switching source can be the front panel key, internal trigger generator or trigger input socket.

    Tone Switching
    The generator can be set to switch between a number of different frequencies in response to a trigger signal. Up to 16 frequencies can be defined. The tone is output while the trigger signal is true, and stops (after completion of a full cycle) when the trigger signal is false. The next tone is output when the trigger signal goes true again. 

  • Technical Specifications

    Frequency
    Frequency Range 1mHz to 10MHz
    Resolution 6 digits or 1mHz
    Accuracy <±10ppm for 1 year, 18°C to 28°C
    Temp Coefficient Typically <1ppm/°C outside of 18°C to 28°C

    All waveforms are derived from a crystal clock using Direct Digital Synthesis. 

    Waveforms

    Sinewave

    Range: 1mHz to 10MHz
    Resolution: 6 digits or 1mHz
    Distortion: <0.3% THD to 20kHz (typically 0.1%), <-45dBc to 300kHz, <-35dBc to 10MHz (typically <-40dBc)
    Spurii: Non harmonically related spurii <-55dBc to 1MHz, <(-55dBc + 6dB/octave) 1MHz to 10MHz
    Output Level: 5mV to 20V pk-pk from 50 Ohms 

    Squarewave

    Range: 1mHz to 10MHz
    Resolution: 6 digits or 1mHz
    Symmetry: variable 20% to 80% in 1% steps
    Aberrations: <5% + 2mV
    Rise & Fall Times: <22ns
    Output Level: 5mV to 20V pk-pk from 50 Ohms

    Triangle

    Range: 1mHz to 1MHz
    Resolution: 6 digits or 1mHz
    Linearity error: <0.5% to 100kHz
    Output Level: 5mV to 20V pk-pk from 50 Ohms

    Positive and Negative Pulse

    Range: 1mHz to 10MHz
    Resolution: 6 digits or 1mHz
    Symmetry: variable 20% to 80% in 1% steps
    Aberrations: <5% + 2mV
    Rise & Fall Times: <22ns
    Output Level: 2.5mV to 10V pk-pk from 50Ω pos or neg only pulses with respect to the DC Offset baseline

    Modulation Modes
    Continuous Cycles of the selected waveform are output at the selected frequency

    Gated

    Non phase-coherent signal keying - output is On while Gate signal is high and Off while low.

    Carrier frequency: From 0.1Hz to 10MHz
    Carrier waveforms: All
    Trigger rep. rate: dc to 100kHz external, dc to 5kHz internal
    Gate source: Front panel MAN TRIG key, Internal Gate Generator, TRIG/GATE input

    Sweep

    Carrier waveforms: All

    Sweep Mode: Linear or logarithmic, single or continuous

    Sweep Width: 0.2Hz to 10MHz. Phase continuous.

    Independent : setting of the start & stop frequency

    Sweep Time: 50ms to 999s (3 digit resolution)

    Markers: Marker variable during sweep. Available at the AUX OUT socket

    Sweep Trigger source: The sweep may be free run or triggered from: front panel MAN TRIG key, TRIG/GATE input

    Amplitude Modulation

    Carrier frequency: 1mHz to 10MHz

    Carrier waveforms: All

    Modulation source: VCA IN socket

    Frequency Shift Keying (FSK)

    Phase coherent switching between two frequencies at a rate defined by the switching signal source.

    Carrier frequency: 1Hz to 10MHz

    Carrier waveforms: All

    Switch repetition rate: dc to 5kHz (internal), dc to 1MHz (external)

    Switching signal source: Front panel MAN TRIG key, Internal Trigger Generator, TRIG/GATE input

    Tone

    The tone is output while the trigger signal is true, and stops (after completion of a full cycle) when the trigger signal is false. The next tone is output when the trigger signal goes true again.

    Carrier waveforms: All

    Frequency list: Up to 16 frequencies between1Hz and 10MHz

    Min. switching time: 1ms per tone

    Switching source: Front panel MAN TRIG key, Internal Trigger Generator, TRIG/GATE input.

    Internal Trigger/Gate Generator

    Period: 0.2ms to 999s (resolution 0.2 ms)

    Waveform: Square wave (1:1 duty cycle)

    Main Output

    Details

    and 

    Specifications

    Output Impedance: 50 Ohms or 600 Ohms switchable

    Amplitude: 5mV-20V pk-pk open circuit (2.5mV-10V into 50Ω)

    Output can be specified as V-HiZ (open circuit value) or V (potential difference) in pk-pk, RMS or dBm. Note that in positive or negative Pulse modes the amplitude range is 2.5mV to 10V pk-pk O/C.

    Accuracy: ±3% ±1mV at 1kHz into 50 Ohms/600 Ohms

    Flatness: ±0.2dB - 500kHz; ±1dB - 10MHz; ±2dB - 20MHz DC

    Offset: ±10V from 50/600 Ohms. DC offset plus signal peak limited to ±10V. Accuracy ±3% ±10mV

    Resolution: 3 digits for both amplitude and offset

    Auxiliary Output

    Details

    and

    Specifications

    Multi-function output user definable to be any of the following:

    Waveform Sync: Outputs a 50% duty cycle squarewave at the main waveform frequency

    Trigger Out: Outputs the current trigger signal

    Sweep Sync: Output a trigger signal at the start of sweep (for synchronising an oscilloscope or chart recorder). Can additionally output a sweep marker.

    Signal Levels: Logic levels of <0.8V and >3V. Sweep Sync is a 3 level waveform, low at start of sweep, high at end of sweep, with a narrow 1V pulse at the marker point.

    Inputs

    Ext Trig/Gate

    Frequency Range: DC to 1MHz for FSK; DC to 100kHz for Gate; DC to 2.5kHz for Tone and Sweep

    Signal Range: Nominal TTL level threshold; max input ±10V

    Min. Pulse Width: 100ns for Gate/FSK; 0.2ms for Sweep and Tone

    Input Impedance: Typically 10k Ohms

    VCA In

    Frequency Range: DC - 100kHz

    Signal Range: 2.5V for 100% level change at max output

    Input Impedance: Typically 6k Ohms


    General Specifications

    Display 20 character x 4 row alphanumeric LCD
    Data Entry Keyboard selection of mode, waveform etc.; value entry direct by numeric keys or by rotary control
    Stored Settings Up to 9 complete instrument set-ups may be stored in battery-backed memory.
    Module Width 295mm (primary console fitting only)
  • PDF Downloads
    File Name File Size Language

    7028 Data Sheet

    485kB

    En

    CalBench Brochure

    4.2MB (Low resolution)

    EN

    CalBench Brochure

    10MB (Higher resolution)

    EN