Ber Measurements Example - Clock/Gate Delay Calibration - Agilent Technologies E4438C Manual

Basic Measurements
BER
data in
LAN or GPIB
www.agilent.com/find/esg
38
In this example, the ESG is configured to provide a Bluetooth modulated RF signal using
the Signal Studio software. The RF test signal consists of a sequence of Bluetooth
modulated DH1 packets with continuous PN9 payload data.
In "loopback" mode, the Bluetooth device receives, demodulates, and decodes the RF
signal transmitted by the ESG. The device then re-transmits the recovered continuous
PN9 payload data in the same packet type that it received from the ESG. The Bluetooth
device's internal test mode must be capable of this operation to perform BER analysis in
this configuration.
The ESA-E series spectrum analyzer with the Bluetooth measurement personality is used
to receive and demodulate the RF loopback signal from the Bluetooth device. Access to
the demodulated signal is provided on the external video out port of the ESA-E.
The clock and gate signals generated by the ESG are used to recover the continuous PN9
payload data portion of the Bluetooth packet for BER analysis. The delay setting found
using the Signal Studio clock/gate delay calibration feature should be used to realign the
clock/gate signals with the demodulated Bluetooth signal at the input of the BER analyzer.
BER measurement example – Clock/gate delay calibration
This example illustrates the procedure for performing clock/gate delay calibration using
Signal Studio. In this example, the measurement setup illustrated in Figure 42 is used.
This is very similar to the test setup illustrated in Figure 40; however, for demonstration
purposes, the Agilent ESA series spectrum analyzer (with the Bluetooth measurement
personality) is used to demodulate the Bluetooth signal generated by the ESG instead of
an actual Bluetooth receiver.
Note: The ESA does not decode the Bluetooth signal. Therefore, packets that implement FEC on the payload data
portion of the packet should not be used in this test setup.
BER BER
Rear panel
clock in gate in
E4438C ESG vector signal generator
• Option 503 250 kHz to 3 GHz frequency range
• Option 602 Baseband generator with 64 MSa
• Option 406 Signal Studio for Bluetooth
• Option UN7 Internal BER analyzer
Figure 42. Example BER measurement set up using the ESA to demodulate the Bluetooth signal
generated by the ESG.
Event 2 Event 1
RF out
ESA-A Series spectrum analyzer
• Option 304 Bluetooth measurement personality
External
video out
RF in