ELECTROMAGNETIC COMPATIBILITY AND MEDICAL DEVICES - Design and Development of Medical Electronic Instrumentation - page 182

+1 5k V

+15 k V

5cm

Nylon Supports

SG

SG

Z1

Z1

2.5cm

L1

L1

TEM Horn

15cm

Z2

Z2

15cm

5cm

5cm 5cm

30cm

30cm

FRONT VIEW

SIDE VIEW

Figure 4.25 Construction details for the Blumlein generator. The TEM horn antenna is formed from two truncated triangular pieces of sin-
gle-sided PCB and edge-soldered to the Blumlein generator board. The spark gap is in a bronze U shape with a bolt that permits the dis-
charge gap to be adjusted.

1 minute with a 1-minute pause between sequences. EFT is capable of inducing EMI
within the device under test over a 60-MHz bandwidth.
A capacitive coupling clamp is used to couple bursts onto signal, data, I/O, and telecom-
munications lines. The coupling clamp is really a 1-m-long metallic plate that couples the
EFT to signal lines without galvanic connection. This plate is suspended by insulator
blocks 10 cm over a reference ground plane. An EFT generator is a relatively complex
piece of equipment. However, for design-time testing, Guettler [1999] proposed a simple
line-disturbance simulator which generates inductive-disconnect transients through the use
off a

fl fluorescent-lamp ballast inductor and a modi fi ed glow-discharge starter. In the circuit

shown in Figure 4.29, a ed by removing

its noise-suppression capacitor. In operation, when SW2 is closed, the glow-discharge
starter SW3 switches on and off

fl fluorescent-lamp glow-discharge starter is modi fi

ff at random. The abrupt current variations through the