BEST 2 RECEIVERS

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BEST 2 RECEIVERS
Jader Monari j.monari_at_ira.inaf.it IRA
-INAF- Bologna Italy-
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The Best-2 platform is composed by 32 receivers 8
cylinders and offers about 1440 m2 of collecting
area. It is primarily aimed to test adaptive
beamforming, calibration techniques, RFIs
algorithms and develop / test some crucial
technology.
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BEST-x GENERAL ARCHITECTURE
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Active device
OIP3gt32dBm
P1dBgt16dBm
NFlt0.2dB
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Balanced Architecture

• A1A2
• Hybrids good phase and amplitude match
• NFA1NFA2 reduction

(NF ILInput_HybridNFA)
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Balanced LNA, the prototype
S22
S21
Sim _at_ 408 MHz Meas _at_ 408 MHz
S21 (dB) 24 24.4
NF (dB) 0.22 0.45
Te (K) 15 31.5
OIP3 (dBm) 34.5 34.5
P1dBout 21.2 21.2
NFlt0.5 between 380MHz and 450MHz
OIP3 gt 34dBm between 350 e 450 MHz
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Full Front end chain
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Inside the FE
RFout
NF0.45dB Tn32K Gain60dB BW16MHz_at_408MHz
OIP3gt33dBm Input RLgt15dB Output RLgt15dB Power
Supply10-15Volt_at_245mA
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Comparision among several FEs
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Mechanical assembly of FE
3 stages FE
Discharges protection circuit
Opt. TX
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Federicos Talk
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IF stages
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IF Receiver specifications

• IP3 spurs product -10dB lower than the system
  thermal noise (KTB) ? IIP3 gt -60dBm
• Auxiliary 408MHz out as monitor
• IF30MHz, OL378MHz
• Pin_ADCBW-35/-30dBm _at_16MHz (ADC Berkeley)
• PinKTB-107dBm (Tb20K) /-100dBm (Tb500K) ?
  GSYSTEM70dB ? GRX35dB
• Digital controlled attenuator (31.5dB with 0.5dB
  step) for match the gain of the different
  receivers and to have the right dynamic range at
  the ADC section
• Only an MMIC model for all the receiver parts (1
  RF, 1 OL and 4 IF)

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Carrier Board
uP
IF

• Power monitor (AD8362) ? AD10dB
• Control of switch on-off each amplifier
  (diagnostic and power-safe via software)

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From the Optical link to the receiver
Light
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Inside the IF receiver.
To A/D
Signal paths RF, IF, OL and digital
controlmonitor.
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Mechanical assembly Carrier-RXO
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Two N-S Cylinders of Carrier-RXO
485 bus
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To LAN
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Conclusions

1. Receivers, analogue optical links and data
   aquisition for BEST-2 are already installed and
   under test and programming

2) Future work will be to design and develop a
new IF to sample directly the 408MHz
3) New mechanical chassis for next generation FE
are going to use to simplify test and assembly
4) New digital uC is going to be used in order
to monitor temperatures and eventually to control
NGs or heaters/peltier to stabilize the FE
environment