Atec Solar-7415-3 - Manual

value of the capacitor as frequency changes from
50 KHz to 400 MHz.
A tuned voltmeter such as an EMI meter is
recommended as the detector for further
isolation of unwanted frequencies, such as
harmonics of the signal generator. If the genera-
tor waveform is “clean.” An untuned meter can be
used if it is terminated in 50 ohms and preserves
a 50 ohm coaxial circuit throughout the
frequency range.
The reactance of the built-in series capacitor from
the generator to the power line terminal presents
very little loss at 50 KHz. At 400 Hz its reactance is
about 362 ohms. Therefore, it represents a path by
which 400 Hz power voltages can be fed back to
damage the output circuit of the signal generator.
To avoid this, one suggestion is to use an isolating
transformer at the output of a low impedance
signal source. Figure 1 shows the use of the
Model 6552-1A Audio Amplifier and the Type
7033-1 Impedance Matching Transformer. This
arrangement can be used for injection levels
up to 20 volts r.m.s. from 50 KHz to 500 KHz with
satisfactory results.
At frequencies above 500 KHz, we recommend
that a 50 ohm signal generator be used as indi-
cated in Figure 2 except that a small capacitor
must be connected in series between the
generator and the Type 7415-3 R.F. Coupler.
Solar Type 7525-1 is 0.1 microfarad, fitted
with BNC connectors.
The reactance of this series capacitor reduces the
power frequency voltage to a safe limit so that
the output circuit of the generator will not be
damaged. At 500 KHz, the r.f. signal is not greatly
attenuated.
At frequencies above 20 or 30 MHz, the connec-
tions from the banana jacks to the test sample will
create discontinuities that cannot be removed
from the setup. It is recommended that the wires
from the banana jacks be less than one inch long
to minimize VSWR anomalies.
DIMENSIONS
2.0" (51 mm) X 2.5" (63.5 mm) plus mounting
flanges x 1.25" (31.25 mm) high.
Application Information
TYPE 7415-3 R.F. COUPLER AND HIGH PASS FILTER
There are those who disagree with the r.f.
conducted susceptibility test setup of Method
CS02 of MIL-STD-462. Homemade rigs have
sprouted to comply with the coupling capacitor
requirement, each with it own disadvantage.
Our little Type 7415-3 R.F. Coupler is the answer.
A neat little box with BNC connectors and a pair
of binding posts, it is rated at 270 V.A.C. at the LINE
terminals and 20 volts PMS into the GEN port.
Looks good and does a fine job.
The test setup diagram of the specification will
result in power frequency voltages at the
voltmeter terminals. If an untuned voltmeter is
used, it is difficult to measure a one volt r.f. signal
in the presence of the a.c. line voltage. It is not
practical to use an EMI meter for this, unless the
Type 7415-3 is placed in series with it. Otherwise,
the power frequency voltage can damage the
input circuit of the EMI meter.
The Type 7415-3 contains a high pass filter in
series with the detector circuit to eliminate power
frequency voltages and allow r.f. signals from
50 KHz to 400 MHz to pass to the EMI meter as
required. The high pass filter consists of three
stages of an R-C network using series capacitors
and shunt resistors. Using resistors instead
of inductors enables the unit to cover a wide
frequency range, with a 40 dB insertion loss in
the pass band. This makes it necessary to multiply
the detected voltage by a factor of 100 for the
measurement of the injected voltage.
The series capacitor in the Type 7415-3 consists
of several styles of capacitors in parallel. Mica,
ceramic and wrapped capacitors exhibit different
characteristics versus frequency and the
combination eliminates the need to change the
TYPE 9132-1 R.F. COUPLER AND HIGH
PASS FILTER
This unit is a high voltage version of the Type
7415-3. It is electrically similar, but in a larger
case and with a rating of 500 VAC at the LINE
terminals and 20 volts rms into the GEN. Port.
Dimensions: 2.88" (73 mm) x 3.06" (78 mm) plus
mounting flanges x 2.0" (51 mm) high.
TYPE 9407-1 A THREE PHASE R.F. COUPLING
NETWORK
MIL-STD-462 notice 5, method CS02 requires
simultaneous coupling of the r.f. susceptibility
69