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Readout Electronics

Last Updated: 15 June 1995 The readout electronics is responsible for the A/D conversion of the signals, intermediate buffering and possible storage of the converted data, and feeding the digital data via an optical fiber link (the HP Gigalink) to the DAQ electronics. In addition to this task, the readout electronics needs to provide regulated power to the FEE, provide timing and control signals for the SCAs on the Hybrids, and provide an interface for the trigger and slow control systems.

Requirement:

Each readout electronics will receive signals from 18 analog inputs and produce digitized values from the inputs. 24 readout electronics units are needed.

Justification:

Distribution of the front end electronics requires the use of 24 readout cards for a total of 416 analog lines from the FEE Hybrids. Therefore, each readout card needs to provide inputs for 18 analog signals.

Requirement:

The system will digitize to 10 bits with an accuracy < 0.1% of full scale, corresponding to 1 LSB for a 10 bit range.

Justification:

Justification of requirement

Requirement:

The readout electronics will accept the analog signals at a rate up to 100 full events/sec.

Justification:

STAR requirement.

Requirement:

The readout electronics will provide the digitized data to the DAQ electronics via an HP Gigalink optical fiber connection in a protocol specified by the FEE -- DAQ interface document.

Justification:

STAR interface specification.

Requirement:

The readout electronics will provide an interface to the trigger system as specified in the Trigger -- FEE interface document.

Justification:

STAR interface specification.

Requirement:

The readout electronics will provide an interface to the controls system via an HDLC link.

Justification:

This link will provide access to several monitors on the detectors that need to be presented to the operators to assure proper functioning of the SVT. In addition, this link provides access to an event memory on the readout electronics, so that an event can be readout via controls, or a pattern can be downloaded to the event memory for testing of the rest of the readout system. Provisions should be made for the readout of temperature sensors and motion/position sensors on the SDD ladder and a geometric ID of the electronics carrier via the slow controls.

Requirement:

The readout electronics will provide the clock and control signals for the SCAs on the Hybrids. These signals need to be driven 10 feet from the readout electronics to the carrier interface Hybrids on the ladders.

Justification:

Space constraints for the on-detector electronics requires that the control and clock signals for the SCA's be generated off the detector. The only connection to the FEE is via the readout card.

Requirement:

The readout electronics will provide for local storage of one full event. This storage can either be filled by the A/D converters or via the controls link. The event in this storage area can be used as an alternative source for the fiber optic link. The data path will be controllable via controls.

Justification:

This feature needs to be available for testing and debugging of the readout and DAQ system.

Requirement:

The readout electronics will provide clean regulated power to the Hybrids.

Justification:

The Hybrids need +5D, +5A, -2, +6, -6 VDC. These voltages need to be generated and regulated by the readout electronics and sent to the carrier interfaces. The readout electronics require +5D, +5A, -5A, -5ECL VDC for internal operation. All voltages will be generated on the readout cards from 8 VDC supplied by power supplies located in the SVT racks.



next up previous
Next: Low Voltage Power Up: Electronics Previous: Dimensions



Claude Andre Pruneau
Thu Oct 12 17:29:54 EDT 1995