24Oct2013 D. Seitz SPP FIELDS RFS Analog Peer Review 24OCT2013 1.
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Transcript of 24Oct2013 D. Seitz SPP FIELDS RFS Analog Peer Review 24OCT2013 1.
24Oct2013 D. Seitz
RFS Analog Section Requirements
4
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
5
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 Input Mux and Amp
7
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
9
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