Erik van der BijProgrammable RF Attenuator in 19-inch rack format
Project description
Programmable attenuator of RF signals with very high voltage range (50mV – 1000 V) for protecting digitizers against damage by high voltage signals.
Four channels with SMA connectors; Three attenuation values: 0, -20dB, -40dB; Bandwidth: DC – 2 GHz.
19-inch rack form factor and controlled and powered over USB.
The primary use of this attenuator is in the Tomoscope and BSM Renovation in the PS of CERN. Only a few will be needed. It will be controlled by USB to specify the required attenuation level.
Front-panel of the RF attenuator. Powered by USB
Top view of 19" module
Specification
- 19-inch, 1U form factor
- 4 channels with SMA connectors
- 3 attenuation values: 0, -20 dB, -40 dB
- Bandwidth: DC – 2 GHz
- Insertion loss: -1.5 dB
- Maximum power dissipation: 1 W (in a 1 ms-long pulse train with 1 J total energy)
- Default attenuation: -40 dB
- Additional protection for the scope by an external RF limiter
- USB input for attenuation selection (USB VID/PID: 1556/0443) and power supply (powered from the USB host)
- Reliability: 10 million mechanical cycles
- 4 indicator LEDs: 3 for showing the current attenuation (per channel)
- Readout of current attenuation
Project information
- Official production documentation: EDA-04173
- Functional Specification - outdated, not corresponding to the design
- Software documentation - CERN only. From outside CERN, download it here: liboattnusb-doc.zip .
- Testing Procedure
- CERN LHC code: HCCAIAD
- Frequently Asked Questions
Contacts
Commercial producers
- This board is currently not sold.
General question about the project
- Erik van der Bij - CERN, general questions
- Tomasz Wlostowski - CERN, designer
Status
| Date | Event |
|---|---|
| 07-05-2012 | First technical discussions for a prototype. |
| 04-07-2012 | Engineering Specification for the Tomoscope & BSM Renovation in PS written. |
| 17-07-2013 | Functional specification written. |
| 20-02-2014 | Project cancelled as an alternative, similar board will be designed by CERN's BE/BI group. |
| 13-08-2018 | BE/BI used a commercial attenuator that is obsolete now. First investigations on new design. |
| 22-05-2019 | Prototype of new design available. |
| 25-08-2020 | Schematic update + analog layout planned for mid-September. |
| 21-10-2020 | Schematics and layout ready for review. |
| 25-01-2021 | Ten attenuator boards ready for testing. |
| 09-11-2021 | Ten attenuator boards tested and put in stock. Drivers and libraries for Linux made. |
| 01-04-2022 | Six in use at CERN. Likely another batch will be produced. |
| 22-06-2022 | Fourty modules will be produced for delivery (without testing) by January 2023. |
| 17-03-2023 | Fourty modules are produced (need to be tested). |
| 24-05-2024 | Fourty modules are produced and tested. |
29 May 2024