Series DS

Fast Switching Direct Synthesizers

CAES' RF microwave series of fast switching direct synthesizers have been designed for use in commercial systems and military systems where demanding performance, high reliability and fast switching are critical.

With switching speeds from 250 nanosecond, the DS delivers ample speed to meet the required response times of EW Simulator, Radar, RCS, ATE and Antenna measurement systems. In addition, the 1 Hz step size capability allows the frequency to be controlled to a high precision.

Custom versions are available with different step sizes and bandwidths. Parallel programming is standard in order to optimize speed. Other interfaces are available as options.

This family of direct synthesizers has been designed for low power consumption and high reliability.

The complete DS synthesizer, with its combination of advanced performance features, is housed in a low profile 5.25” high rack- mountable chassis or optional 1.75” or 3.5” chassis for some models. For specialized applications the DS can be tailored to suit custom bands and physical outlines due to its modular architecture. The touch screen front panel version provides simple control and versatility. SatCom and digital radio equipment, as well as in high-performance frequency agile surveillance, radar and communications equipment.

Our optional coherent switching synthesizer, unlike other technologies available, can perform coherent switching down to 1 Hz of the synthesizer. Previous to this breakthrough, coherent resolutions have been limited to larger steps because switching time performance degraded as resolution is decreased. This design from CAES overcomes this limitation and provides a new tool for Signature Measurement Technologists.

This new synthesizer can be ordered with many options and can be custom configured to meet your requirements. As an example, an FM modulator can be added to the coherent unit to make it interchangeable between Simulator and Signature Measurement applications.

Key Tech Specs
Power, Dimensions and Environmental
  • AC input voltage 120 VAC to 240 VAC auto switching, 47-400 Hz
  • DC input voltage +10Vdc, +6 Vdc, +15 Vdc, -12 Vdc (measured at synthesizer for modular configuration)
  • Ripple on DC 5 mVpp max 50 Hz to 50 kHz, 50 mVpp max 50 kHz to 10 MHz
  • Operating temperature 0˚ to +50˚ centigrade
  • 19 inch rack mount, 2U or 3U high depending on options
  • Modular configuration 10.63” x 9.5” x 4.5”
  • Approximate weight 36 lbs rack mount, 17 lbs modular configuration


Typical Performance Specifications
  • Frequency range 10 MHz to 20.48 GHz, option to 40.96 GHz
  • Custom bandwidths
  • Output power +10 dBm ±2.5 dB
  • Spurious
    • 75 dBc 10 MHz to 5120 MHz
    • 70 dBc 5120 to 10240 MHz
    • 65 dBc 10240 to 20480 MHz
    • 60 dBc 20480 to 40960 MHz
  • Harmonics -15 dBc, -50 dBc optional
  • External reference 10 MHz or 100 MHz
  • Frequency accuracy with internal reference ±0.2 ppm over temperature, 1 ppm/year aging
  • External reference accuracy required for phase locking internal reference ±1 ppm @ +3 ± -3 dBm power level
  • Frequency accuracy with external reference, same as external reference for step sizes 250 kHz to 20 MHz; same as external reference ±1 x 10¯12 for 1 Hz step size
  • Step size from 1 Hz
  • Switching speed 500 ns
  • Summary alarm TTL low = alarm for modular configuration, red LED= alarm on front panel for rack configurations


Touch Screen Computer Functions
  • Frequency entry display
  • Reference select
  • Local/parallel J1/ GPIB
  • Frequency step up or step down
  • Alarm indicator
  • Power on/off
  • Sweep
  • Range
  • Direction
  • Dwell time
  • Trigger mode
  • Step size
  • Stop sweep
  • Resume sweep
  • Ping-pong
  • Jump frequencies
  • Dwell time
  • Trigger mode
  • Stop ping-pong
  • Resume ping-pong


Typical Phase Noise (dBc/Hz)
Offset 10GHz 18GHz 40GHz
100 Hz -90 -84 -77
1 kHz -110 -104 -97
10 kHz -120 -114 -107
100 kHz -120 -114 -107
1 MHz -130 -124 -117
10 MHz -136 -130 -123
  • Broadband 0.010 to 40.96 GHz
  • Very low phase noise -120 dBc/Hz typical at 10 kHz, offset at 10 GHz
  • Switching speed 500 nano seconds
  • Step sizes from 1 Hz
  • Low profile chassis or modular configuration
  • Custom bands and step sizes
  • Low spurious
  • Parallel BCD programming
  • Low power consumption, 100 watts from AC mains
  • Coax strobe input and selection switch
  • RF output mute
  • Universal AC power supplied


  • IEEE-488/GPIB, Ethernet
  • Internal 100 MHz reference with sample output
  • Phase Coherent switching
  • Phase Continuous SwitchinG(bandwidth restricted)
  • AM, PM, FM & Pulse Modulation
  • Front panel control and display can be custom configured
  • Touch Screen Computer (TSC) front panel for rack mount unit
  • Digital frequency sweep via TSC
  • FM with four operational modes; WBDC, WBAC, NBDC, NBAC
  • Modulation bandwidth 10 MHz
  • Expanded FM deviations
  • Power flatness +/-1dB
  • Coherent stepping to 1 Hz
  • Downloadable list mode with fast list triggering and ready feedback signal
  • Differential interface
  • Linear AC power supply
  • Binary control
  • Harmonic filter banks
  • Switching speeds from 250 nano-seconds (Consult Factory)
  • Noise floor -140 dBc/Hz @ 18 GHz

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