Hologic QDR 4500 - Analog to Digital Board

QDR
®
4500 Technical Manual
2-30
Table 2-22. Analog Digital Converter Board/Integrator Multiplexor Board
Interconnection Descriptions
Signal
Signal
(see Note 1)
Description
ADC
Pins
I/M
PINS
MA1, MA2
MB1, MB2
MC1, MC2
MD1, MD2
MUX0- MUX3
GPL1, GPL2
IN0, IN1
IN6, IN7
IN2, IN3
IN4, IN5
IN8 IN9
IN10, IN11
IN14, IN15
Selects integrator channels to be
returned to the Analog/Digital
Converter.
JP4-1, JP4-3
JP4-13, JP4-15
JP4-5, JP4-7
JP4-9, JP4-11
JP4-17, JP4-19,
JP4-21, JP4-23
JP4-29, JP4-31
JP7-1, JP7-3
JP7-13, JP7-15
JP7-5, JP7-7
JP7-9, JP7-11
JP7-17, JP7-19,
JP7-21, JP7-23
JP7-29, JP7-31
MGN1, MGN2 IN12, IN13 Controls integrator/multiplexor
gains.
JP4-25, JP4-27 JP7-25, JP7-27
LTCH1,
LTCH2
IN16 Latches control signals on
Integrator/ Multiplexor.
JP4-33
JP4-37
JP7-33
JP7-37
INTEG IN18 Controls signal integration. JP4-35 JP7-35
DISC IN19 Discharges the integrating
capacitors.
JP4-39 JP7-39
TSTEN IN20 Test signal used to verify the
operation of the integrators and
multiplexor when no X-rays are
present.
JP4-41 JP7-41
BB0
BB1
BB2
BB3
Integrator signals to the
Analog/Digital Converter.
JP2-2
JP2-6
JP2-10
JP2-14
JP11-2
JP11-6
JP11-10
JP11-14
+15V
15V_RET
-15V
Powers the amplifiers and switches
of the Integrator/Multiplexor
board and powers the Solid State
Detector boards.
JP1-5
JP1-4
JP1-3
JP10-5
JP10-4
JP10-3
+5V Powers the digital circuitry of the
Integrator/Multiplexor board.
JP1-2 JP10-2
GND JP1-1 JP10-1
Note 1. Some signal names are labeled differently on different schematic drawings.
Analog To Digital Board
The Analog To Digital (ADC) board converts analog signals received from the
Integrator/Multiplexor board to a digital format.
Analog signals from the Integrator/Multiplexor board are applied to differential amplifiers on the
ADC board in four groups of up to 64 channels. Outputs from the differential amplifiers are
combined in a final multiplexor consisting of four analog switches. The multiplexed signals pass
through a programmable gain amplifier and summing amplifier before being applied to an A/D
converter. A one volt fixed DC offset is inserted at the summing amplifier to insure that no