User manual

a7 The use of a telescopic antenna for increasing the input sensi-
tivity is recommended from approx. 50 MHz on (fully extended)
up to more than 1GHz (pushed together).
Caution !
Make sure that the circuits in/at which you perform your measu-
rements are separated from the mains galvanically via an isolati-
on transformer. Never connect the inputs/outputs (BNC) directly
to the mains, to chassis to which voltage may be applied and to
circuits operated without transformers (galvanic isolation). Cau-
tion danger to your life!
Observe the maximum input ratings. Never connect voltages of
more than 88 Vrms to channel C and 5 Vpp to the channels A and
B. Before each measurement check all BNC jacks for damage or
short-circuit.
If the source resistance or the line capacitance of a direct connec-
tion between the measurement object and the frequency counter
are unknown, especially at high frequencies, use a 1:10 probe with
a low capacitance for the inputs A and B. Do not use a probe for
channel C as its relatively high impedance might produce incorrect
measurement results.
A strategy for coaxial cables to keep measurement errors low when
measuring low frequencies is the use of a terminator. The impedan-
ce of this terminator, which is connected directly to the frequency
counter, should correspond to the impedance of the signal source
and of the cable.
Example: Output resistance of a frequency generator = 50 ohm,
Resistance of the coaxial cable used = 50 ohm
==> Resistance value of the terminator = 50 ohm
B Working with the frequency counter/commissioning
Three inputs are available for measuring frequencies: channel (CH)
A, channel (CH) B and channel (CH) C. By using the push-button
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