Duncan Instruments Canada Ltd
Duncan Instruments Canada Ltd.
Electronic Measurement Solutions since 1968
ISO 9001


Model 645 - 50MHz Arbitrary Waveform/Function Generator

The 645 is the high performance 50MHz Waveform Generator.It can create stable, precise,clean and low distortion sine waves by using DDS(Direct Digital Synthesis) Technology. With fast rise and fall times up to 25MHz for square waves and 200KHz for linear ramp waves.The 645 also can generate variable-edge-time pulses up to 10MHz and generate complex custom waveforms.


BNC Model 625A Signal Generator


  • 50MHz Sine, 25MHz Square & 10MHz arbitrary Waveforms
  • 14-bit,125 Msa/s, 256K-point Arbitrary Waveform
  • Pulse,Ramp, Triangle, Noise & DC Waveforms
  • Linear & Logarithmic Sweeps & Burst Operation
  • AM,FM,PM,(PSK), FSK & PWM Modulation Types
  • Amplitude Range, 20 mVpp to 20 Vpp into Open Circuit
  • Remote Control via USB, LAN or Optional GPIB programming
  • Graph Mode for Visual Verification of Signal Settings
  • 16-bit Data Output via Pattern Out
  • Free Waveform Editor Software WaveCrafter
  • User Friendly Operation
Waveform Characteristic
  Display Graphic mode for visual verification of signal settings
1 Micro Hz to 50MHz Capability Standard Waveform Sine, Square, Ramp, Triangle, Pulse, Noise, DC
Amplitude Flatness (Relative to 1K)
0.1dB (<100kHz) Built-in Arbitary Waveform Exponential Rise and Fall, negative ramp, Sin(x)/x, Cardiac
0.15dB (<5MHz)
Common Characteristic
0.3dB (<20MHz) Frequency Resolution 1 MicroHz
Harmonic Distortion [2][3] (Unit:dBc)
DC to 20KHz, -70(<1Vpp) -70(>=1Vpp) Amplitude Range 10mVpp to 10Vpp in 50Ohm
20KHz to 100KHz, -65(<1Vpp) -60(>=1Vpp) 20mVpp to 20Vpp in Hi-Z
100KHz to 1MHz, -50(<1Vpp) -45(>=1Vpp) Accurac[1][2] (at 1KHz) +/-1% of setting +/- 1mVpp
1MHz to 20MHz, -40(<1Vpp) -35(>=1Vpp) Units Vpp, Vrms, dBm
20MHz to 50MHz, -35(<1Vpp) -30(>=1Vpp) Resolution 4 digits
Total Harmonic Distortion[2][3]
DC to 20KHz, output >=0.5Vpp THD +N<=0.06% DC Offset Range(peak AC+DC) +/-5V in 50 Ohm
DC to 1MHz -70dBc +/- 10V in Hi-Z
1MHz to 50MHz Accuracy[1][2] +/-2% of offset setting +/-0.5% of amplitude setting
-70sBc + 6dB/octave Resolution 4 digits
Phase Noise (10K Offset)
-115/dBc/Hz, typical when f>=1MHz, V>=0.1Vpp Main Output Impedance 50 Ohm typical
1 MicroHz to 25MHz Isolation 42 Vpk maximum to earth
Rise/Fall Time
< 10ns Protection short-circuit protected; overload automatically disables main output
<2% Internal Frequency Reference Accuracy[5] +/-10ppm in 90 days
Variable Duty Cycle
20% to 80% (to 10MHz) +/-20ppm in 1 year
40% to 60% (to 25MHz) External
Frequency Reference
Standard/Option Standard
1% of period = 5ns(@50% duty) External Frequency Input Lock Range 10 MHz +/- 500 Hz
200ps when f>= 11MHz, V>=0.1Vpp Level 100mVpp ~ 5Vpp
Ramp, Triangle
1 MicroHz to 200 KHz Impedance 1KOhm typical, AC coupled
<0.1% of peak output Lock Time <2 Sec
0.0% ~ 100.0% External Lock Range 10 MHz
500 MicroHz to 10 MHz Frequency Output Level 632 mVpp(0dBm), trpical
Pulse Width
20 ns minimum Impedance 50Ohm typical, AC coupled
10 ns res. (period <= 10s) Phase Offset Range -360 to 360°
Variable Edge Time
<10 ns to 100 ns) Resolution 0.001°
<2% Accuracy 8ns
200 ps when f>=500KHz, V>=0.1Vpp
20 MHz typical Modulation Type AM,FM,PM,FSK, PWM, Sweep and Burst
1 MicroHz to 10 MHz AM Carrier Sine, Square, Ramp, Arb
2 to 256K Source Internal / External
14 bits (including sign) Internal Modulation Sine, Square, Triangle, Noise, Arb
Sample Rate
125 MSa/s Frequency(Internal) 2mHz to 20KHz
Min. Rise/Fall Time
30ns typical Depth 0.0% ~ 120.0%
<0.1% of peak output FM Carrier Sine, Square, Ramp, Arb
Setting Time
<250ns to 0.5% of final value Source Internal / External
6ns + 30 ppm Internal Modulation Sine, Square, Triangle, Noise, Arb
4 waveforms * 256K points Frequency(Internal) 2mHz to 20KHz
Pattern Mode Characteristic
Deviation DC ~ 25MHz
Maximum Rate
50MHz   PM Carrier Sine, Square, Ramp, Arb
TTL Compatible >=2Kohm   Source Internal / External
Output Impedance
110Ohm Typical   Internal Sine, Square, Triangle, Noise, Arb
2 to 256 K   Modulation Arb
  Frequency(Internal) 2mHz to 20KHz
Power Supply CAT II 110V ~ 240VAC +/-10%   Deviation 0.0 ~ 360°
Power Cord Freq. 50Hz to 60Hz   PWM Carrier Pulse
Power Consumption 50VA Max.   Source Internal / External
Operating Environment 0°C to 55°C   Internal Modulation Sine, Square, Triangle, Noise, Arb
Storage Temperature -30°C to 70 °C   Frequency(Internal) 2mHz to 20KHz
Interface (Standard) USB, LAN, (Optional) GPIB   Deviation 0% ~100% of pulse width
Language SCPI-1993, IEEE-488.2   FSK Carrier Sine, Square, Ramp, Arb
Dimensions 107 (H) x 224 (W) x 380 (D) mm   Source Internal / External
Weight 4.08Kg   Internal Modulation 50% duty cycle Square
Safety Designed to IEC61010-1, EN61010-1, UL61010-1   Frequency (Internal) 2mHz to 100KHz
Warm-up Time 1 hour   External Modulation input voltage Range +/-5V full scale
One USB cable, one pattern generator cable, one line cord, one CD (including manual, WaveCrafter software)   Input Resistance 8.7KOhm typical
  Bandwidth DC to 20KHz
  Sweep Waveform Sine, Square, Ramp, Arb
Optional GPIB Interface Card   Type Linear or logarithmic
    Direction Up or down
    Sweep Time 1 ms ~ 500 Sec
    Trigger Internal, External or manual
    Marker Falling edge of sync signal(programmable frequency)
    BURST[7] Waveforms Sine, Square, Triangle, Noise, Arb
    Type Internal/External
    Start/Stop Phase -360 to +360°
    Internal period 1 MicroS ~ 500Sec
    Gated Source External Trigger
    Trigger Source Internal, External or Manual
  Trigger Input Level TTL Compatible
Add 1/10th of output amplitude and offset spec per °C for operation outside the range of 18°C to 28 °C
  Slope Rising or Falling(Selectable)
  Pulse Width > 100ns
Autorange enable
  Impedance >10KOhm, DC Coupled
DC offset set to 0V
  Latency <500ns
Spurious output at low amplitude is -75 dBm typical

Trigger Output


Level TTL Compatible into >=1KOhm
Add 1 ppm/°C average for operation outside the range of 18°C ~ 28°C
  Pulse Width >400ns
FSK uses trigger input (1 MHz maximum)
  Output Impedance 50Ohm Typical
Sine and square waveforms above 6 mMHz are allowed only with an "infinite burst court
  Maximum Rate 1 MHz
  Fan-out <=4 Array

Instrument selection

Last modified March 2009.
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