Shilpa Bollineni, Glen Langston, John Ford, Randy McCullough and

Paul Demorest

DATA ACQUISITION ON THE 43M TELESCOPE

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DATA ACQUISITION ON THE 43M TELESCOPE

• The Digital Acquisition System is a clone of GUPPI(Green Bank Ultimate Pulsar Processing Instrument).

• It was developed to be placed on the 43m telescope in the feed-box.

• Why we did this?

1) The limitation with the fiber modem on the frequency range which will be eliminated and we can observe at higher range.

2) We will have more dynamic range in the system as the S/N will be better.

3) As the prime-focus box is controlled we will have a more stable environment.

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Heater Control Circuit

Teledyne VT6 Vacuum Gauge

Lakeshore Model 218

Temp Monitor

Bias Cards(2)

Vacuum Sensor #1

RFI Shielded Box

Net Burner

Heater #2

Bias # 17

Temp Sensor # 6

BEE2

IBOB 1

IBOB 2

Vacuum Pressure Monitor (1)

Gate Voltage Monitor (9)

DC +/-15V ACAC

Controller

Induction Motor Blower

AC

RF INPUT

Sunpower GT CryoCooler

Dewar

Temperature Monitor (2)

CAT5CAT5

DC Supply (48V,10A)

IP Power StripIP Power Strip

OFF

ON

# 2

# 4

Fig 1: Block diagram of the system

Fiber to cat5

Fiber to cat5

SWITCHSWITCH

WUPPI

Remote

Monitoring

Cryocooler

Power supply

Overview of the components

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1) WUPPI

a) IBOB’s (Sampling)

1) 8-bit sampling.

2) Bandwidth of 800MHZ.

b) BEE2 (Data Processing)

1) We have 4k channel FFT.

2) full polarization

c) IP power strip (Remotely control the power of the hardware)

d) Dual Synthesizer (800 MHz clock)

Overview of the components

e) Ethernet switch

f) 1PPS converter (Fiber to copper converter)

g) Ethernet converter (Fiber to Cat5)

2) Remote Monitoring:

a) Net Burner (Embedded networking device)

b) Temperature Monitoring Device (Lakeshore)

3) Refrigerator components:

a) Controller (for the refrigerator on the Dewar)

b) DC power supply (To the refrigerator)

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The RFI shielded box has the dimensions 21(w)x24(d)x22(h) inches

6Fig 2: Mechanical model of the RFI shielded box

FRONT VIEW

Fig 3: Front-view of the box 7

SMA

Fiber cable data O/P

Brackets for mounting

8Fig 4: Inside the box

• Front View • Back View

Fiber to copper converter for 1PPS

XAUI cables ST connectors (Fiber)

IP Boot Bar

4 channel transceiver

9Fig 5: Transceiver module/Fiber Fan-out

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04

/18

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Fig 6: Mechanical View of the Front-End Box

Front-end receiver Back-end Data Processing

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Different phases of testing

a) RFI test passed.

1) Frequency range: 20 MHz to 6.5 GHz no emissions.

b) Data was taken in the lab (plots follow).

b) Next the box will be placed in the 43m control room.

c) Finally it will be placed in the Front-end box so we can process the data at the antenna.

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Results

Fig 7: Spectrum @ 800MHz Fig 8: Spectrum @ 220MHz

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Fig 9: Pulsar 0329+54

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Summary and Future work• WUPPI was developed and successfully

tested in the lab.

• After integration with the front-end it will be placed on the telescope.

• Working on replacing Roach with the IBOB’s and BEE2 in the WUPPI.

• Worked with the Parkes spectrometer design.

1)Built a 2K channel, 800MHz dual polarization version.

2)Introduced the 1SFA concept from GUPPI into the design.

15 Fig 10: Spectrum on Roach

16 Fig 11: test signal @ 611 MHz

Acknowledgement

• Glen Langston

• John Ford

• Jeff Cromer

• Randy Mccullough

• Jason Ray

• Dennis Egan

• Gary Anderson

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