GBT OPERATIONS PROCEDURES

Number: OP-06

Title: Signal Path Setup

Last Revision: 27Nov01

Info

Refer to the GBT Electronics Schematic for assistance in tracing the signal path from front end to backend components.

 

General

The following table lists the basic Cleo applications required to set up the signal path for completing the type of observation shown. Additional applications (Signal Switch Selector, IF Manager, etc.) may be needed initially during your set up depending on observer preferences or to check settings associated with a specific component.

 

OBSERVATION TYPE

NORMAL CLEO APPLICATIONS REQUIRED

Continuum

  • LO1

  • Receiver

  • IF Rack

  • Converter Rack*

  • Analog Filter Rack*

  • Backend (DCR or Spectrometer)

* Only required when using the Spectrometer or if specified by the observe when using the DCR

Spectral Line/Pulsar

  • LO1

  • Receiver

  • IF Rack

  • Converter Rack

  • Analog Filter Rack (only required when using Spectrometer)

  • Backend (Spectrometer or Spectral Processor)

 

Signal Path Set Up (LO1 thru Analog Filter Rack)

    LO1: 

STEP

ACTION

1

Launch the CLEO LO1 application: CLEO launch®I.F./L.O®LO1

2

Check and/or set the following:

  • Select LO1 tab (A or B) (observer specified)

  • Set switches for signal flow to chosen receiver (blue path)

  • Set IF center frequency (obtain value from table or engineer)

  • Set F0 (sky frequency) value (observer specified)

  • Select lower sideband (rx <10GHz) or upper sideband (rx >10GHz)

  • Adjust power (dbm) to get ~5v at receiver

  • Check State/Status indicators

  • Check commanded LO1A/B values (IF+F0=Commanded value after running "prepare" or starting a scan)

    Receiver IF Center Frequency Table: 

RECEIVER

FREQ (MHz)

RECEIVER

FREQ (MHz)

PF1 (342.5 MHz)

1080

S-Band (1.73-2.60 GHz)

6000

PF1 (450 MHz)

1080

C-Band (3.95-5.85 GHz)

3000

PF1 (600 MHz)

1080

X-Band (8-10.1 GHz)

3000

PF1 (800 MHz)

1080

Ku-Band (12-15.4GHz)

3000

L-Band (1.15-1.73 GHz)

3000

K-Band (18-26.5 GHz)

6000

    Receiver: 

STEP

ACTION

1

Launch the desired CLEO Receiver application: CLEO launch®receivers®select receiver (Prime Focus: PF1 or PF2; Gregorian: 1-2(L), 2-3(S), 4-6(C), 8-10(X), 12-18(Ku), 18-26(K))

2

Check and/or set the following:

  • Set switches for signal flow through receiver

  • Set CAL control and power level (High/Low) (observer specified)

  • Set polarization and filter (observer specified)

  • Check LO power (5v + .5v) (adjust via power box (dbm) on LO1)

  • Check cryogenics (15K and 50K values should be ~15/50 respectively) 

  • Check State/Status indicators

    IF Rack: 

STEP

ACTION

1

Launch the CLEO IF Rack application: CLEO launch®I.F./L.O.®I.F. Rack

2

Check and/or set the following:

  • Select channels desired corresponding to the receiver used

  • Check signal flow switch setting

  • Select filter (observer specified)

  • Ensure laser power is on for channels selected

  • Check RF power (~1v) (balance and/or adjust attenuation if needed) 

  • Balance "off source" as necessary

  • Check State/Status indicators

Note: Steps concerning the Converter and Analog Filter Racks may be skipped if using the DCR.

    Converter Rack: 

STEP

ACTION

1

Launch the CLEO Converter Rack application: CLEO launch®I.F./L.O.®Converter Rack

2

Check and/or set the following:

  • Select converter module(s) (CM1-16) and synthesizer(s) (G1-8) (observer specified)

  • Select optical receiver inputs (observer specified)

  • Set frequency for selected synthesizer(s) (observer specified)

  • Select converter module output filter(s) (observer specified)

  • Check RF power (~1v) (adjust attenuation as necessary)

  • Check State/Status indicators

Note: Skip steps for setting up the Analog Filter Rack if using the Spectral Processor.

    Analog Filter Rack: 

STEP

ACTION

1

Launch the CLEO Analog Filter Rack application: CLEO launch®I.F./L.O.®Analog Filter Rack

2

Check and/or set the following:

  • Select 100MHz converters and filters (observer specified)

  • Select samplers and filters corresponding to converters chosen

  • Check SG power and CF power (~ 1v) (adjust attenuation as necessary)

  • Set sample rates (1 sec preferred)

  • Check power supplies (values should be near those listed) 

  • Check State/Status indicators

Signal Path Set Up (Backends)

    DCR: 

STEP

ACTION

1

Launch the CLEO DCR application: CLEO launch®Backends/®DCR

2

Check and/or set the following:

  • Check signal and phase selection parameters (observer specified) (set at DCR and via Switch Signal Selector application)

  • Select channels desired (same as on IF Rack)

  • Set sampler value types (TP,SP,Gain, and TSys); check values

  • Check State/Status indicators

    Spectrometer: 

STEP

ACTION

1

Launch the CLEO Spectrometer application: CLEO launch®Backends/®Spectrometer

2

Check and/or set the following:

  • TBD

  • Check State/Status indicators

Spectral Processor: 

STEP

ACTION

1

Launch the CLEO Spectrometer application: CLEO launch®Backends/®Spectral Processor

2

Check and/or set the following:

  • TBD

  • Check State/Status indicators

 

Prepared by: Dave Rose

Last modified: 27Nov01