High-Power Synthesized Sweepers for RF and Microwave Component Testing
Filed under Sweepers
RF and microwave component characterization requires precise frequency control, broad spectral coverage, and sufficient signal amplitude. High-power synthesized sweepers serve as critical tools in these workflows, allowing test engineers to evaluate passive networks and active devices. By delivering high output power directly from the source, these instruments eliminate the need for external amplifiers, maintaining high signal-to-noise ratios and preventing phase distortion. This guide examines the engineering reasons for selecting high-power sweepers, focusing on how they address common testing challenges such as path loss, active device compression, and sweep speed requirements. It highlights how these capabilities are realized in industry-standard signal generators.
- Frequency Coverage Range
- 10 MHz to 20 GHz
- Maximum Leveled Power
- +17 dBm (83623B)
- Minimum Settable Power
- -110 dBm (83623B with Option 001)
- Frequency Resolution
- Down to 1 Hz
Overcoming Path Loss in Passive Networks
Testing complex passive networks—such as high-order filters, multi-way couplers, and long coaxial runs—introduces substantial path attenuation. Using a standard signal source often results in the output signal dropping close to the noise floor of the receiving instrument. While adding an external preamplifier can boost the signal, it introduces unwanted variables, including phase drift, gain flatness errors, and additional noise.
A high-power synthesized sweeper solves this by supplying robust leveled output power directly. For instance, the Keysight 83623B provides up to +17 dBm of calibrated leveled power. This high direct output preserves the signal-to-noise ratio across the entire measurement path, ensuring clean and accurate transmission and reflection measurements without external amplification hardware.
Characterizing Active Device Compression Limits
Determining the linear operating range and 1 dB compression point of RF amplifiers requires a source that can deliver both high power and highly precise amplitude control. The signal generator must drive the amplifier from its linear region well into compression.
Instruments designed for this purpose offer a wide dynamic range. The Keysight 83623B, when equipped with the Option 001 step attenuator, allows power levels to be set from -110 dBm up to +17 dBm. This wide power sweep range enables engineers to evaluate both low-level linear behavior and high-power saturation on a single port. Furthermore, amplitude resolution down to 0.01 dB, as supported by the Keysight 83752B, provides the precision necessary to pinpoint exact compression thresholds.
Synthesized Accuracy and Sweep Flexibility
Modern microwave testing demands both the spectral purity of a synthesizer and the speed of an analog sweep oscillator. Synthesized swept-signal generators combine these characteristics. They support multiple sweep modes, including step sweep, list sweep, and analog ramp sweep, allowing compatibility with both digital measurement systems and analog scalar network analyzers.
The Keysight 83624A covers 2.0 GHz to 20.0 GHz with a frequency resolution of 1 kHz, making it suitable for high-performance coaxial measurements. For broader testing spanning down to the RF range, the Keysight 83752B offers coverage from 10 MHz to 20 GHz with a 1 Hz frequency resolution. These units also support advanced modulation, including pulse, amplitude, and frequency modulation, allowing complex pulsed RF testing of components under representative operating conditions.
Example instruments
Frequently asked questions
- Why choose an integrated high-power sweeper over a low-power sweeper with an external amplifier?
- An integrated high-power sweeper, such as the 83623B, provides a calibrated, leveled output directly from the instrument. External amplifiers introduce uncalibrated gain drift, harmonic distortion, and increased noise floor, which degrade measurement accuracy.
- What frequency resolution is available on these synthesized sweepers?
- Frequency resolution depends on the model and options. The 83624A features a standard 1 kHz resolution, while the 83752B delivers 1 Hz resolution. The 83623B offers 1 kHz as standard, which can be upgraded to 1 Hz with Option 008.