Programmable RF Attenuator in VME
Project description
Programmable attenuator of RF signals with very high voltage range (50
mV – 1000 V) for protecting digitizers against damage by high voltage
signals.
Four channels with SMA connectors; Three attenuation values: 0, -20, -40
dB; Bandwidth: DC – 2 GHz.
VME form factor with I2C management bus. No VME-bus interface, only
power supply used.
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 a CTRV card that will give out pulses that specify which attenuation level to use. If no pulses are received within a certain period, the attenuator will automatically switch to the highest possible attenuation level.
Main Features
- VME form factor with I2C management bus (ELMA VME crate). VME bus is not used.
- 4 channels with SMA connectors.
- 3 attenuation values: 0, -20, -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.
- 3 LEMO 00 inputs for attenuation selection. A pulse on an input selects its corresponding attenuation.
- Reliability: min. 30 million mechanical cycles.
- Safety timeout: no attenuation selection command within a given time
(factory programmed)
automatically selects 40 dB attenuation. Such situation might happen when
the front-end with the CTR driving the card is rebooted or powered off. - 4 indicator LEDs: 3 for showing the current attenuation, one for indicating a safety timeout.
- Readout of current attenuation, total number of relay switching
operations and number of
safety timeouts triggered over the I2C management bus.
Project information
- Official production documentation: EDA-0
- Functional Specification
Contacts
Commercial producers
- This board is not sold.
General question about project
- Erik van der Bij - CERN
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. |
16-10-2020 | See other project called Programmable RF Attenuator in 19 inch rack format as alternative solution. |
Erik van der Bij - 16 October 2020