24Oct2013 D. Seitz

SPP FIELDSRFS Analog

Peer Review 24OCT2013

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24Oct2013 D. Seitz

FIELDS RFS Analog Breadboard

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24Oct2013 D. Seitz

RFS Block Diagram

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24Oct2013 D. Seitz

RFS Analog Section Requirements

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RFS Analog requirements RTI = Signal input connectorInput impedance 50 Ohms +/-5%

Noise RTI < 10nV above 100kHz; < 4nV above 1MHz

4Vpp output bandwidth > 18MHz

Functional Requirements:• Five inputs (V1, V2, V3, V4, SCM)• Two independent ADC signal conditioning chains• Each ADC chain:

• Single ended measurement of any selected input• Difference measurement of any two selected inputs

(V1-V4)• Selectable high or low gain for V1-V4 inputs• Balanced differential drive to ±2V range 12 bit ADC

24Oct2013 D. Seitz

RFS Analog Section Components

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All components are SQPL and at least 100krad

except for output balun transformer – will have to be designed and built in-house at

UCB SSL

24Oct2013 D. Seitz

RFS Analog Breadboard Schematic

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24Oct2013 D. Seitz

RFS Analog Input Mux and Amp

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Mux Ron x Cout = 29MHz with ±6 supply - increase supplies to ±8?

AD8001 has plenty of BWBut needs ±5, not ±6

Attempted differential measurement between coax center and shield with shield terminated through larger resistor does not work – explore values of RSAT (e.g. R85)

24Oct2013 D. Seitz

RFS Analog Diff and Gain Amps

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LM6172 requires lower R values for best performance – reduce to 499Ω

Need to reduce impedance between LM6172 and output mux- DC couple!

24Oct2013 D. Seitz

RFS Analog Output Mux and Amp

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Output mux Ron x Cout also limits BW - increase supply to ±8 - CD4052 dual 4:1 has ½ Cout but hard to procure…

Output LM6172 will be reconfigured as 2 pole lowpass and R42 reduced to 50Ω for ÷2; 4Vpp => 2Vpp for ADC

Balun transformer (not shown) yet to be tested - using Mini-Systems commercial part for BB but will have to design in-house for EM and flight

24Oct2013 D. Seitz

RFS SCM input buffer

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Nothing here yet!

Plan to standardize on input buffers used on TDS and DFB