Positioning The Dut (Device Under Test); Sensitivity Vs. Frequency - Sierra Wireless MC5725 Hardware Integration Manual

RF Integration

Positioning the DUT (Device Under Test)

To achieve meaningful results, the device must be positioned
such that the peak of the receive antenna pattern is pointed
toward the source antenna. Theoretically, the best way to
accomplish this is to modify the DUT so that antenna output is
through coaxial cable. The device is then rotated until the
receive power is maximized.
Alternate path loss calculation method
Path loss can also be calculated, without modifying the DUT,
by using the transmit capabilities of the unit. This method of
calculation is possible because the position that maximizes
transmitter power provides a sufficiently accurate location for
receiver desense measurements. The unit is placed in a call and
set to generate peak output power, either through a test mode,
or by configuring the base station simulator to issue the appro‐
priate command. The unit is then positioned for maximum
power as determined by the call box.

Sensitivity vs. frequency

For the MC57xx, sensitivity is defined as the input power level
in dBm that produces a FER (Frame Error Rate) of 0.5%. Sensi‐
tivity should be measured at all CDMA frequencies across
each band. For example, Figure 3‐3 illustrates sensitivity in the
US PCS band. There are 25 physical channels with a spacing of
50 KHz; the first CDMA channel is CH25.
For the MC87xx, sensitivity is defined as the input power level
in dBm that produces a BER (Bit Error Rate) of 2% (GSM) or
0.1% (UMTS). Sensitivity should be measured at all GSM /
UMTS frequencies across each band, as shown in Figures 3‐4
through 3‐11.
Rev 1.9.1 Feb.09 Proprietary and Confidential 45
In the event of a discrepancy in values between this guide and the Product Specification Document (PSD), the PSD takes precedence.