LO Path
- Updated2024-09-19
- 2 minute(s) read
The PXIe-5840 has two tunable local oscillators (LO) for the RF input and RF output signal paths. The following high-level block diagram represents the common design of these two LO paths.
The LO path consists of the following individual blocks:
- Synthesizer
- Signal distribution and LO source selection
- LO out signal path
Synthesizer
The onboard synthesizer of the PXIe-5840 consists of integrated tunable voltage control oscillators (VCO), phase‑locked loops (PLL), and RF dividers. The combined circuitry is capable of tuning from 9 kHz to 6,000 MHz.
Signal Distribution and LO Source Selection
The LO source is distributed to the downconverter or upconverter and the LO output signal path through the Signal Distribution. You can select the LO source as either the onboard synthesizer or the LO IN front panel connector. Refer to the External Local Oscillator section of the Local Oscillators topic for more information about using an external LO with the LO IN front panel connector.
LO Out Signal Path
The PXIe-5840 supports the export of the LO signal to the LO OUT front panel connector. The LO output signal path can either export the LO directly from the synthesizer or through a programmable gain stage. Refer to the Interconnecting Multiple PXIe-5840 RF Channels (Homogeneous Channel Types) topic for more information on using the features of the LO output signal path.
Related Information
- Local Oscillators
There are separate local oscillators (LOs) on the PXIe-5840 for each RF signal path. The separate LOs allow for different LO frequencies between RF input and RF output channels.
- RF Output Subsystem
The PXIe-5840 has two configurable RF paths comprised of an independent vector signal analyzer (RF input) path and vector signal generator (RF output) path. The following high-level block diagram represents the PXIe-5840 RF output path.
- Interconnecting Multiple PXIe-5840 RF Channels (Homogeneous Channel Types)
There are certain RF applications that benefit from phase coherency or phase synchronization between multiple RF input and/or RF output channels.