Manual

Table Of Contents
ANSI C63.17-2006
Methods of Measurement of the Electromagnetic and Operational Compatibility of UPCS Devices
C.2.2
C.2.3
C.2.4
EUT and companion device provisions
The test system of this example requires that the EUT and the companion device provide the necessary
trigger signals for the arbitrary waveform generator. In this example, the EUT and companion device form
a cordless telephone system—a handset and a telephone base. The user interface is on the handset, and all
communications channel initiation begins at the handset. The base provides a beacon to which the handset
locks, and notifies the handset using a slow data channel on the beacon signal when the base has, for
example, an incoming ringing signal. The base maintains system timing through the beacon, to which the
handset synchronizes.
In this example, the base is always the source for the frame-sync signal, whether the base is the EUT and
the handset is the companion device, or the handset is the EUT and the base is the companion device. The
frame-sync signal is generated within the base by the hardware timing section, and is exactly synchronous
with the start of the first slot of the frame.
In this example, the signal required to trigger the arbitrary waveform generator element of the RF vector
signal generator is produced by the controller within the handset. The handset has the user interface, and
when the user presses the TALK button to establish the communications channel, the handset establishes
the communications channel to the base. The controller within the handset is timing-aware, and is
configured to generate a single pulse on an otherwise unused digital I/O signal in the frame prior to the first
transmit burst. This pulse is used to trigger the change of the interference profile generated by the arbitrary
waveform generator. The functionality of the pulse and the trigger is independent of whether the handset is
the EUT and the base is the companion device, or the base is the EUT and the handset is the companion
device.
Interface element
The RF vector signal generator trigger inputs are assumed to be general-purpose digital inputs with a
reasonably low input impedance. It is necessary to buffer the frame-sync and pretransmit-frame signals,
rather than routing them directly from the EUT and companion device to the RF vector signal generator
trigger inputs. In addition, the timing markers generated by the RF vector signal generator on the digital
data and control port of the arbitrary waveform generator are very short duration pulses; if these pulses
were displayed on a four-channel digital oscilloscope with sufficient span to see multiple frames, and thus
to show the deferral or initiation of a transmit pulse at the moment of an interference profile change, the
pulses would be too short to be captured.
These problems are addressed using a multipurpose interface element between the vector signal generator
and the rest of the system. On the trigger lines, buffering is provided within the interface element using
CMOS logic that can drive trigger inputs. Displayable marker signals are generated using the interface
element by means of ICM7555 or similar short-pulse-triggerable one-shot devices. The ICM7555 also
facilitates the conversion to CMOS levels of the LVDS-level differential signals of the marker signals
coming from the digital data and control port of the arbitrary waveform generator. The port on the arbitrary
waveform generator is a 68-pin male VHDCI and the construction of the interface element is facilitated by
using a similar connector. Cable assemblies are commercially available.
Software
LabVIEW
software
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used in the example is publicly available on the web, in the National Instruments
developer’s zone area.
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Search on UPCS from the search window in http://www.ni.com. The software is
provided in the public interest to assist in the understanding of this example and these means by which the
tests of Clause 7 and Clause 8 may be implemented. The use and configuration of the software is the
responsibility of the user.
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LabVIEW is a trademark of National Instruments, Incorporated.
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This information is given for the convenience of users of this standard and does not constitute an endorsement by the IEEE of this
product. Equivalent technology may be used if it can be shown to lead to the same results.
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Copyright © 2007 IEEE. All rights reserved.
Licensed to Sid Sanders. ANSI order X_30788. Downloaded 11/19/2007 2:45 PM. Single user license only. Copying and networking prohibited.