Rohde & Schwarz SMH Series RF Signal Generators
3 models with full specifications from Rohde & Schwarz.
The Rohde & Schwarz SMH series comprises high-performance analog and vector RF signal generators designed for laboratory testing, receiver characterization, and high-precision calibration. Spanning a frequency range starting at 100 kHz and reaching up to 4.32 GHz, these instruments serve engineers in research, development, and production environments. While the base SMH provides a solid foundation for standard 2.0 GHz analog testing, the SMHU and SMHU58 models extend frequency limits, improve resolution, and offer advanced phase noise and vector modulation options to meet more demanding RF requirements.
- Frequency Range
- 100 kHz to 4.32 GHz
- Minimum Frequency Resolution
- 0.1 Hz
- Maximum Output Power
- +13 dBm
- Impedance
- 50 Ω
Models in this series
Frequency Coverage and Resolution
The models within this series scale in frequency range and resolution depending on the application requirement. The base Rohde & Schwarz SMH covers a frequency range of 100 kHz to 2.0 GHz with a frequency resolution of 1 Hz. For higher frequency and finer step requirements, both the Rohde & Schwarz SMHU and the Rohde & Schwarz SMHU58 extend their frequency capabilities from 100 kHz up to 4.32 GHz, while refining the frequency resolution to 0.1 Hz.
Output Power and Spectral Purity
Output capabilities and noise floors vary across the series. The Rohde & Schwarz SMH has an output range of -137 dBm to +13 dBm with a phase noise of -124 dBc/Hz at a 20 kHz offset on a 1 GHz carrier.
For applications requiring extreme spectral purity, the Rohde & Schwarz SMHU delivers a phase noise of <-140 dBc/Hz (typical -143 dBc/Hz) at a 20 kHz offset on a 1 GHz carrier. It also features a wider standard output power range of -140 dBm to +13 dBm, with overrange capabilities up to +19 dBm. The Rohde & Schwarz SMHU58 maintains a similar power range of -140 dBm to +13 dBm but adds fine-grained amplitude control with an amplitude resolution of 0.1 dB.
Modulation and Sweep Options
The modulation and sweep features distinguish the three models for specific testing workflows:
- Rohde & Schwarz SMH: Supports AM, FM, Phase Modulation (φM), and Pulse Modulation. Sweeps are restricted to digital step sweep modes for frequency and level.
- Rohde & Schwarz SMHU: Features standard AM, FM, Phase, and Pulse modulation, supported by two independent internal modulation synthesizers. This model adds a modulation frequency sweep mode (linear/logarithmic) alongside standard frequency and level sweeps. It supports external AM (DC to 50 kHz), external FM (DC to 100 kHz standard, up to 1 MHz in broadband mode), and external phase modulation (20 Hz to 20 kHz).
- Rohde & Schwarz SMHU58: Adds vector (I/Q) modulation capabilities alongside traditional AM, FM, Phase, and Pulse modulation. It incorporates external BNC female inputs on the panel to accept external I/Q signals.
Frequently asked questions
- Which models in the SMH series support vector modulation?
- Only the Rohde & Schwarz SMHU58 supports vector (I/Q) modulation. It includes external BNC female I/Q inputs specifically for this purpose.
- What are the main phase noise differences between the SMH and the SMHU?
- The Rohde & Schwarz SMHU provides significantly lower phase noise, rated at <-140 dBc/Hz (typically -143 dBc/Hz) at a 20 kHz offset and 1 GHz carrier. The Rohde & Schwarz SMH is rated at -124 dBc/Hz under the same conditions.
- Do these signal generators include reference oscillators?
- Yes. The Rohde & Schwarz SMH contains a standard 10 MHz reference oscillator, whereas the Rohde & Schwarz SMHU utilizes a highly stable 10 MHz OCXO reference oscillator requiring approximately 10 minutes of warm-up time.