RF Signal Cables W. Udo Schröder, 2011 Principles Meas/Electronics 2 RG59/U coaxial cable (BNC) Stiffer than RG58 75 Ohm impedance Dual shielded cable: copper braid (60%) over foil 22 AWG copper covered steel center conductor Amphenol RG58 coaxial cable (BNC) Impedance 50 Ohm Black PVC cable, tinned copper center conductor & braid for high frequency performance Nickel-plated connector body & Gold-plated center pin contact Insulation: Solid PE (Polyethylene) Rating < 500 V Outer Diameter: inches nominal Velocity of Propagation: 66% (50ns/m) LEMO RG174 coaxial cable (LEMO) Impedance50 ohms Inner Conductor Diameter0.48 mm Dielectric Diameter1.52 mm Shield Diameter2.23 mm Capacitance pF/meter (30.5 pF/foot) Minimum Operating Temperature -40 C (-40.0 F) Maximum Operating Temperature 75 C (167.0 F) Jacket Diameter2.79 mm Jacket MaterialPVC Velocity Ratio66% Corestranded

Connectors for Coax Signal Cables W. Udo Schröder, 2011 Principles Meas/Electronics 3 LEMO Léon Mouttet Push-pull connectors BNC Bayonet Neill-Concelman Bayonet mount locking mechanism

HV Supply Cables W. Udo Schröder, 2011 Principles Meas/Electronics 4 MHV connectors: 5000 volts DC and 3 amperes.voltsDCamperes Hazards: HV on exposed central pin, ground disconnects before power. Do not use! SHV connectors: Do not mate to BNC connectors, Power disconnects before ground.

W. Udo Schröder, 2011 Principles Meas/Electronics 5 Signal Transmission Lines inner conductor outer conductor/shield outer conductordielectric medium outer casing Coaxial cables/transmission lines  traveling waves in cavity resonators Wave equation ideal line (R0, 1/G 0): z L: inductivity C: capacity G: conductance dielectric, depend on diameter and dielectric Signal propagation speed (speed of light): c -1  5 ns/m Characteristic resistance Z 0 =Ohmic resistance! For R≠0, Z 0 () complex Impedance Z 0 = 50, 75, 93  used for timing, spectroscopy,… U Elementary replacement circuit for transmission line per unit length

Real Cables W. Udo Schröder, 2011 Principles Meas/Electronics 6 U Traveling waves Pulse distortion in long cables

W. Udo Schröder, 2011 Principles Meas/Electronics 7 Impedance Matching RdRd R load RdRd sender receiver For impedance matching, R load =Z 0, cable looks infinitely long: no reflections from end. For mismatch, R load ≠ Z 0, reflection at end, traveling back, superimpose on signal Polarity of reflected signal R load =0, ∞

Pulse Splitting/Adding W. Udo Schröder, 2011 Principles Meas/Electronics 8 R1R1 U in R2R2 U out U in R R R R Z0Z0 Z0Z0 Z0Z0 U out Also use in reverse as 3-way adder

W. Udo Schröder, 2011 Principles Meas/Electronics 9 Impedance Mismatch Receiver input impedance R load ≠ Z 0,  use additional Ohmic termination in parallel R load R term L L Open end: R load = ∞ Input and reflection equal polarity, overlap for t > 2T cable T cable = 2L/c Short: R load =0, Input and reflection opposite polarity, superposition = bipolar Multiple (n) reflections attenuated by R -n

W. Udo Schröder, 2011 Principles Meas/Electronics 10