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20 MHz DDS Function Generator

20 MHz DDS (direct digital synthesis) Sweep Function Generator with Arb Function.

SKU BK4045B Category

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20 MHz DDS Function Generator from B&K Precision.

The BK4045B is a high-performance, 20 MHz DDS (direct digital synthesis) function generator with arbitrary waveform capability.

The device generates stable and precise sine, square, triangle, and arbitrary waveforms. It also provides variable output voltages from 0 to 10 Vpp into 50 Ω (up to 20 Vpp into open circuit), linear and logarithmic sweep, AM/FM modulation, a built-in counter, and a continuously variable DC offset that allows the output to be injected directly into circuits at the correct bias level.

Separate output amplitude and DC offset amplifiers let you set a large DC offset (e.g. ± 4.99 V ) with a small amplitude output signal (e.g. 10 mV). This is a feature that is typically found in more expensive generators.

The BK4045B combines a traditional DDS and a true arbitrary generator in one unit, giving you the benefits of both technologies. Using DDS technology, waveforms can be generated with high frequency resolution at a low price. Due to the inherent limitations of this architecture, not all points from the waveform memory are used, and points may be skipped at higher frequencies. This leads to significantly more jitter and higher distortions on non-repetitive waveforms. Sometimes small details of the waveforms stored internally will be missing from the output signal. The true arbitrary waveform section generates point-by-point waveforms with lower jitter, high resolution, and true representation of the required waveform.

Due to the arbitrary waveform capability of the BK4045B, the instrument is able to generate low-jitter square waves with greater edge stability. The improved signal integrity allows these generators to be used for simulating reliable clock signals, generating triggers, or validating serial data buses.

Product Features

  • 12-bit, 50 MSa/s, 1k point arbitrary waveform generator
  • Sine and square waveforms up to 20 MHz
  • Triangle/ramp waveforms up to 2 MHz
  • Bright colour display with waveform preview
  • Linear and logarithmic sweep
  • AM/FM modulation
  • Independent output and DC offset amplifiers allow for small amplitude output signals with large DC offsets
  • Low-jitter square wave generation
  • Adjustable duty cycle
  • Output ON/OFF button
  • Internal/external triggering
  • Gate and burst mode
  • Built-in counter
  • USB interface
  • SCPI-compliant command set
  • Arbitrary waveform editing software and remote control application software provided
  • Short circuit and overvoltage protection on all inputs and outputs
Frequency Characteristics
Sine 0.01 Hz to 20 MHz
Square 0.01 Hz to 20 MHz
Triangle 0.01 Hz to 2 MHz
Resolution 6 digits* or 10 mHz
Accuracy (Sine) 0.002% (20 ppm) at < 500 Hz: 0.001% + 0.006 Hz
Output Characteristics
Amplitude Range 10 mVpp to 10 Vpp (into 50 Ω);
20 mVpp to 20 Vpp (open circuit)
Amplitude Resolution 3 digits (1,000 counts)
Amplitude Accuracy ± 2% ± 20 mV of programmed output from 1.01 V – 10 V
Flatness ± 0.5 dB to 1 MHz
± 1 dB to 20 MHz
DC Offset Range -4.99 V to 4.99 V (into 50 Ω)
DC Offset Resolution 10 mV, 3 digits
DC Offset Accuracy ± 2% ± 10 mV (into 50 Ω)
Output Impedance 50 Ω ± 2%
Output Protection Protected against short circuit or accidental voltage applied to the main output connector
Waveform Characteristics
Harmonic Distortion
(for sine wave at 5 Vp-p into 50 Ω)
0 – 1 MHz, < -60 dBc
1 MHz – 5 MHz, <-50 dBc
5 MHz – 12 MHz, <-45 dBc
12 MHz – 20 MHz, <-50 dBc
Square Rise / Fall Time ≤ 20 ns (10% to 90% at full amplitude into 50 Ω)
Duty Cycle Square: 20% - 80% to 2 MHz
Triangle: 1% - 99% in 1% steps, up to 200 kHz
Symmetry Accuracy at 50% ± 1%
Jitter (Square) < 100 ps rms (cycle-to-cycle, typical)
Arbitrary Waveform Characteristics
Sampling Rate 20 ns to 50 s
Vertical Resolution 12 bits
Accuracy 0.001%
Resolution 4 digits
Waveform Length 2 to 1000 points
Operating Modes
Continuous Output continuous at programmed parameters
Triggered Output quiescent until triggered by an internal or external trigger, at which time one waveform cycle is generated to programmed parameters. Frequency of waveform cycle is limited to 1 MHz.
Gate Same as triggered mode, except waveform is executed for the duration of the gate signal. The last cycle started is completed.
Burst 2-65535 cycles
Trigger Source Trigger source may be internal, external, or manual. Internal trigger rate 0.1 Hz – 1 MHz (1 us – 10 s)
Modulation Characteristics
Internal Amplitude Modulation 0.1 Hz – 20 kHz sine, square, or triangle waveform
External Amplitude Modulation 5 Vp-p for 100% modulation, 10 kΩ input impedance
Internal Frequency Modulation 0.1 Hz – 20 kHz sine, square, or triangle waveform
External Frequency Modulation 5 Vp-p for 100% modulation, 10 kΩ input impedance
Sweep Characteristics
Sweep Shape Linear or Logarithmic, up or down
Sweep Time 10 ms to 100 s
Input and Output
Trigger IN TTL compatible
Maximum rate 1 MHz
Input impedance 1 kΩ
Minimum width > 50 ns
Sync Out TTL pulse at programmed frequency; 50 Ω source impedance
Modulation IN 5 Vp-p for 100% modulation
10 kΩ input impedance
DC to > 20 kHz minimum bandwidth
Counter Characteristics
Range 50 Hz to 50 MHz
Resolution Auto ranging, up to 8 digits
Accuracy ± 0.02% ± 2 digits
Sensitivity 25 mVrms typical
Memory Storage 20 instrument settings
Arbitrary Memory 1,000 points in flash memory
Power Requirements 100 V – 240 V AC ± 10%, 47-63 Hz
Operating Temperature 0 °C to 50 °C
Storage Temperature -10 °C to 70 °C
Humidity 95% R.H. 0 °C to 30 °C
Dimensions W x H x D 213 x 88 x 210 mm
Weight 2.5 Kg
Electromagnetic Compatibility Meets EMC Directive 2004/108/EC, EN55011, EN55082
Safety Meets Low Voltage Directive 2006/95/EC, EN61010
Included accessories Power cord, USB (type A to B) interface cable, certificate of calibration

*For square wave, resolution is up to 4 digits when frequency is > 20 kHz.

Note: All specifications apply to the unit after a temperature stabilization time of 15 minutes over an ambient temperature range of 23 ºC ± 5 ºC. 
Specifications are subject to change without notice.

BK4045B Specifications

BK4045B User Manual