Test Block Diagram and Hardware Description

Transcription

1 Test of PAF Receiver and Downconverter Contents Test Block Diagram and Hardware Description... 1 Test Software... 1 Hardware Configuration... 2 Catalog of Tests... 4 RF Power Monitoring... 6 IF Power Monitoring... 7 Link Behavior and Dynamic Range... 8 Sensitivity and Stability Tests... 9 Summary of Test Results Recommendation for maintenance and repair Appendix A Test Block Diagram Date: , reporter: B. Shillue Purpose: Measurements of PAF Receiver, Link, and Roach Data Acquisition to assess the current status of the hardware, especially the low noise amplifiers and the digital downconverter blades. The outcome of this testing will be a summary to serve as the basis fro recommended maintenance and reapir of the hardware items. Test Block Diagram and Hardware Description See Figure 12 Test Setup of PAF in GBO Outdoor Test Facility) in Appendix A. Notes on the test setup: Receiver mounted in the positioner ring Receivr pointed to hot load LO set to 1450 MHZ for all measurements Water cooling was not required with outdoor temperatures arounf 50 deg F, and the OTF windows opena dn heaters off. Test Software Used PAF Monitor and Control Labview GUI executable (dated ) which resided on Albacore PC located in the GBT control room. Access to Albacore was by remote desktop. The executable is stored in folder c:\paf Monitor and Control, and data was stored in a folder

2 Hardware Configuration It is critically important to correctly record and track the status of the channel mapping from dipole to blade to Roach. During observing this mapping is important to performing thand understanding the beamformning, distribution of element weights, etc. Also, the mapping of the downconverter blade channels to the respective Roach channels is important so the correct set of coefficient can be applied to accomplish the reconstruction of the sidebands from I/Q IF band. For the most recent (January 2018) telescope testing, and for these OTF tests, the mapping from blade to Roach was the nominal mapping. Blade A channels 1 8 connected to Roach1 channels 0 >7. Corresponding channels for blades B,C,D, E are connected to Roach 2,3,4 and 5. For the most recent telescope tests, and for these OTF tests, the mapping of dipoles to blades was changed from the nominal mapping. For reference the nominal mapping is shown below in figure 1, and then the changes from that mapping are specified in Figure 2 (for these tests) and Figure 3 (configuration setup at the completion of these tests). Dipole Blade Channel Dipole Blade Channel X1 A1 Y1 C5 X2 A2 Y2 C6 X3 A3 Y3 C7 X4 A4 Y4 C8 X5 A4 Y5 D1 X6 A6 Y6 D2 X7 A7 Y7 D3 X8 A8 Y8 D4 X9 B1 Y9 D5 X10 B2 Y10 D6 X11 B3 Y11 D7 X12 B4 Y12 D8 X13 B5 Y13 E1 X14 B6 Y14 E2 X15 B7 Y15 E3 X16 B8 Y16 E4 X17 C1 Y17 E5 X18 C2 Y18 E6 X19 C3 Y19 E7 spare C4 spare E8 Figure 1 Nominal mapping of dipoles to downconverter blade channels. Colors are added to indicate that there are two sets of dipole polarization and five blades.

3 Dipole Blade Channel Dipole Blade Channel X1 A1 Y1 C5 X2 A2 NC C6 X3 A3 Y3 C7 X4 A4 Y4 C8 X5 A4 Y5 D1 X6 A6 Y6 D2 X7 A7 Y7 D3 NC A8 Y8 D4 X9 B1 Y9 D5 X10 B2 Y10 D6 X11 B3 Y11 D7 X12 B4 Y12 D8 X13 B5 Y13 E1 X14 B6 Y14 E2 X15 B7 X8 E3 X16 B8 Y16 E4 X17 C1 Y17 E5 X18 C2 Y18 E6 X19 C3 Y19 E7 2Y C4 spare E8 Figure 2 Mapping of dipole to downconverter blade channel used for these OTF tests. Deviations from nominal mapping are shownin red. Note that Y15 dipole is not connected to a blade channel, X8 and Y2 are remapped, and A8, C6, and E8 have no LNA or dipole inputs.

4 Dipole Blade Channel Dipole Blade Channel X1 A1 Y1 C5 X2 A2 Y2 C6 X3 A3 Y3 C7 X4 A4 Y4 C8 X5 A4 Y5 D1 X6 A6 Y6 D2 X7 A7 Y7 D3 NC A8 Y8 D4 X9 B1 Y9 D5 X10 B2 Y10 D6 X11 B3 Y11 D7 X12 B4 Y12 D8 X13 B5 Y13 E1 X14 B6 Y14 E2 X15 B7 Y15 E3 X16 B8 Y16 E4 X17 C1 Y17 E5 X18 C2 Y18 E6 X19 C3 Y19 E7 X8 C4 spare E8 Figure 3 Mapping of dipole to downconverter blade channel which was setup after the completion of these OTF tests. Deviations from nominal mapping are shown in red. Note that Y15 dipole is now connected, X8 is mapped to the spare channel at C4 (due to faulty A8 channel). Catalog of Tests Time File name Description Configuration 1 10:31 pm PAF Monitors , 10_31_23AM. csv PAF Monitors , 10_31_23AM.xlsx 2 12:20 pm PAF Monitors , 12_20_46PM.csv PAF Monitors , 12_20_46PM.xlsx 3 1:24 pm PAF Monitors , 01_24_10PM.csv Initial testing: all channels monitoring, bit locking, and attenuation dynamic range testing Stability and sensitivity test Fig. 2 Radome, Hot load Fig. 2 Radome, Hot load Cold sky Test of Channel A8 Fig. 2

5 4 1:29 pm PAF Monitors , 01_29_50PM.csv 5 1:47 pm PAF Monitors , 01_47_16PM.csv 6 1:49 pm PAF Monitors , 01_49_42PM.csv 7 2:55 pm PAF Monitors , 02_55_49PM.csv 8 3:13pm PAF Monitors , 03_13_36PM.csv Table 1 List of Tests Radome Receiver in access position facing door Test of Channel C6 Fig. 2 Radome Receiver in access position facing door Test of Channel E7 Fig. 2 Radome Receiver in access position facing door Retest of Channel E7 Test after reconfiguration Hot/Cold test of Y15 Fig. 2 Radome Receiver in access position facing door Fig. 3 Radome, Hot load Fig. 3 Radome, Hot load Cold sky

6 RF Power Monitoring Figure 4 RF Power for all dipoles/channels. Rf power is tightly grouped between 50 and 55 dbm except for the five channels flagged: A8, C6, E2, E7, E8.

7 IF Power Monitoring E2 and E A8,C6,E8 80 9:33:07 AM 9:33:50 AM 9:34:33 AM 9:35:17 AM 9:36:00 AM 9:36:43 AM 9:37:26 AM Figure 5 IF Power for all dipoles/channels. IF power is tightly grouped between 20 and 30 dbm at the outset (for attenuation setting = 2 db), except for the same five channels as noted. Then the attenuation is varied from 2 db to 30 db and all channels behave as expected.

8 Link Behavior and Dynamic Range :31:41 AM 9:32:24 AM 9:33:07 AM 9:33:50 AM 9:34:33 AM 9:35:16 AM Blade A Ch1 I RMS Blade A Ch2 I RMS Blade A Ch3 I RMS Blade A Ch4 I RMS Blade A Ch5 I RMS Blade A Ch6 I RMS Blade A Ch7 I RMS Blade A Ch8 I RMS Blade B Ch1 I RMS Blade B Ch2 I RMS Blade B Ch3 I RMS Blade B Ch4 I RMS Blade B Ch5 I RMS Blade B Ch6 I RMS Blade B Ch7 I RMS Blade B Ch8 I RMS Figure 6 Blade A and B response of the Vrms (response of the Roach measurement of A/D output level), as the attenuator is varied from 2dB to 20 db. (Not shown channel A8 had no response)

9 :31:41 AM 9:32:24 AM 9:33:07 AM 9:33:50 AM 9:34:33 AM 9:35:16 AM Blade C Ch1 I RMS Blade C Ch2 I RMS Blade C Ch3 I RMS Blade C Ch4 I RMS Blade C Ch5 I RMS Blade C Ch6 I RMS Blade C Ch7 I RMS Blade C Ch8 I RMS Blade D Ch1 I RMS Blade D Ch2 I RMS Blade D Ch3 I RMS Blade D Ch4 I RMS Blade D Ch5 I RMS Blade D Ch6 I RMS Blade D Ch7 I RMS Blade D Ch8 I RMS Blade D Ch8 Q RMS Blade D Ch8 Q RMS Blade E Ch1 I RMS Blade E Ch2 I RMS Blade E Ch3 I RMS Blade E Ch4 I RMS Blade E Ch5 I RMS Blade E Ch6 I RMS Blade E Ch7 I RMS Blade E Ch8 I RMS Figure 7 Blade C, D, and E response of the Vrms (response of the Roach measurement of A/D output level), as the attenuator is varied from 2dB to 20 db. (Not shown channel E8 had no response) (E2, E7, C6 values fall below the others) Sensitivity and Stability Tests This test involved the following steps: Activate receiver monitoring and bit lock all channels with receiver pointe staright up into hot load Open the roof Wait two minutes Close the roof Wait approx minutes Thus, in the first part of the test the senitivity of the channels can be measured by plotting the total power deflection as the load chnages from hot load to cold sky. In the second part of the test, an extended measure of the power levels versus time is acquired for all channels.

10 50 11:19:41 AM 11:22:34 AM 11:25:26 AM 11:28:19 AM 11:31:12 AM RF Blade A Ch1 RF Blade A Ch2 RF Blade A Ch3 RF Blade A Ch4 RF Blade A Ch5 RF Blade A Ch6 RF Blade A Ch7 RF Blade A Ch8 Figure 8 Hot and Cold Load for Blade A. All channels deflect as expected except for A8

11 11:19:41 AM 11:22:34 AM 11:25:26 AM 11:28:19 AM 11:31:12 AM RF Blade B Ch1 RF Blade B Ch2 RF Blade B Ch3 RF Blade B Ch4 RF Blade B Ch5 RF Blade B Ch6 RF Blade B Ch7 RF Blade B Ch8 RF Blade D Ch1 RF Blade D Ch2 RF Blade D Ch3 RF Blade D Ch4 RF Blade D Ch5 RF Blade D Ch6 RF Blade D Ch7 RF Blade D Ch8 Figure 9 Hot and Cold Load for Blade B and D. All channels deflect as expected.

12 45 11:19:41 AM 11:22:34 AM 11:25:26 AM 11:28:19 AM 11:31:12 AM RF Blade C Ch1 RF Blade C Ch2 RF Blade C Ch3 RF Blade C Ch4 RF Blade C Ch5 RF Blade C Ch6 RF Blade C Ch7 RF Blade C Ch8 RF Blade E Ch1 RF Blade E Ch2 RF Blade E Ch3 RF Blade E Ch4 RF Blade E Ch5 RF Blade E Ch6 RF Blade E Ch7 RF Blade E Ch8 Figure 10 Hot and Cold Load for Blade C and E. All channels deflect as expected except for C6, E2, E7, and E8. (Note E3 had a momentray instability. This was not pursued further).

13 20 11:16:48 AM 11:24:00 AM 11:31:12 AM 11:38:24 AM 11:45:36 AM 11:52:48 AM 12:00:00 PM Q Blade A Ch1 Q Blade A Ch2 Q Blade A Ch3 Q Blade A Ch4 Q Blade A Ch5 Q Blade A Ch6 Q Blade A Ch7 Q Blade A Ch8 Q Blade B Ch1 Q Blade B Ch2 Q Blade B Ch3 Q Blade B Ch4 Q Blade B Ch5 Q Blade B Ch6 Q Blade B Ch7 Q Blade B Ch8 Q Blade C Ch1 Q Blade C Ch2 Q Blade C Ch3 Q Blade C Ch4 Q Blade C Ch5 Q Blade C Ch6 Q Blade C Ch7 Q Blade C Ch8 Q Blade D Ch1 Q Blade D Ch2 Q Blade D Ch3 Q Blade D Ch4 Q Blade D Ch5 Q Blade D Ch6 Q Blade D Ch7 Q Blade D Ch8 Q Blade E Ch1 Q Blade E Ch2 Q Blade E Ch3 Q Blade E Ch4 Q Blade E Ch5 Q Blade E Ch6 Q Blade E Ch7 Q Blade E Ch8 Figure 11 Stability of all channels. Stability into a stable load is good for all channels.

14 Summary of Test Results All behavior or the RF power, response to attenuation, IF power, and the Vrms in the Roaches is *as expected* in 35 of the 40 channels. Five of the channels have anomolies: A8, C6, E2, E7, E8. Subsequent testing (tests #3 #6) demonstrated that: A8: Fault is in the downconverter blade, there is no optical power coming from the blade on that channel. C6: There was no dipole/lna input for the tests of this channel. Further test revealed this downconverter channel is working well. E2: The LNA was not working in this channel (Y14). When a functioning dipole/lna was conencted to this channel, the response was good. E7: The LNA was not working in this channel (Y19). When a functioning dipole/lna was conencted to this channel, the response was good. Y15 dipole/lna was found to be working and was reconnected to blade E3 E8: There was no dipole/lna input for the tests of this channel. Further test revealed this downconverter channel is working well. Recommendation for maintenance and repair The recommendation is as follows: 1. Remove the blade A and ship to CDL for repair of channel Replace LNAs in Y14 and Y19 with spare, ship non workign units to CDL for repair and replace.

15 Appendix A Test Block Diagram Figure 12 Test Setup of PAF in GBO Outdoor Test Facility