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General Information Regarding the CE Marking
General Infor-
mation
Regarding
the CE Mar-
General Information Regarding the CE Marking
ROHDE & SCHWARZ measuring instruments comply with regulations of the
EMC Directive. ROHDE & SCHWARZ is basing the conformity assessment
on prevailing generic and product standards. In cases with potentially
different thresholds, ROHDE & SCHWARZ instruments apply more rigorous
test conditions. Thresholds for business and commercial sectors as well
as small business are applicable for interference emission (class 1B). As to
the interference immunity, the standard thresholds for the industrial sector
apply. Measurement and data lines connected to the measuring instrument
significantly affect compliance with specified thresholds. Depending on the
respective application, utilized lines may differ. In regards to interference
emission and immunity during measurements, it is critical that the following
terms and conditions are observed:
1. Data Cables
It is imperative to only use properly shielded cables when connecting
measuring instruments and interfaces to external devices (printers, compu-
ters, etc.). Unless the manual prescribes an even shorter maximum cable
length, data cables (input/output, signal/control) may not exceed a length
of 3m and may not be used outside of buildings. If the instrument interface
includes multiple ports for interface cables, only one cable at a time may be
connected. Generally, interconnections require double-shielded connecting
cables. The double-shielded cable HZ72 (available at ROHDE & SCHWARZ) is
well suitable as IEEE bus cable.
2. Signal Cables
In general, measuring cables for the transmission of signals between measu-
ring point and measuring instrument should be kept as short as possible.
Unless an even shorter maximum cable length is prescribed, signal cables
(input/output, signal/control) may not exceed a length of 1m and may not be
used outside of buildings. All signal cables must be shielded (coaxial cable
RG58/U). It is important to ensure proper ground connection. Signal genera-
tors require the use of double-shielded coaxial cables (RG223/U, RG214/U).
3. Impact on Measuring Instruments
If strong high-frequency electric and magnetic fields are present, it may
occur despite diligent measurement setup that unwanted signal units are
injected into the measuring instrument via connected measuring cables. This
will not damage the ROHDE & SCHWARZ measuring instrument or put it out
of operation. In some cases, these circumstances may cause the measuring
value to slightly exceed specifications.
4. RF immunity of oscilloscopes.
4.1 Electromagnetic RF field
The influence of electric and magnetic RF fields may become visible (e.g. RF
superimposed), if the field intensity is high. In most cases the coupling into
the oscilloscope takes place via the device under test, mains/line supply,
test leads, control cables and/or radiation. The device under test as well as
the oscilloscope may be effected by such fields. Although the interior of the
oscilloscope is screened by the cabinet, direct radiation can occur via the
CRT gap. As the bandwidth of each amplifier stage is higher than the total
–3 dB bandwidth of the oscilloscope, the influence of RF fields of even higher
frequencies may be noticeable.
4.2 Electrical fast transients / electrostatic discharge
Electrical fast transient signals (burst) may be coupled into the oscilloscope
directly via the mains/line supply, or indirectly via test leads and/or control
cables. Due to the high trigger and input sensitivity of the oscilloscopes,
such normally high signals may effect the trigger unit and/or may become
visible on the TFT, which is unavoidable. These effects can also be caused by
direct or indirect electrostatic discharge.
