LISA-C2 series and FW75-C200 - System Integration Manual
UBX-13000620 - R21
Early Production Information
Features description
Page 71 of 103
3.4.4.4
Response, receiver power level estimation:
After the time interval, the command response is the RMS received power level (minimum, average and
maximum level) expressed in dBm. The average level is calculated during the whole time interval
The receiver power levels(min, avg, max) range from -95 to -30 dBm. Although in this case, the protocol stack is
inoperative, the reported results can be assumed to be good estimates.
Rx path test should have a clearly specified input signal strength level ( e.g. -50dBm ) of a CW waveform.
Expected accuracy of the measurement level will be approximately +/- 1.0 dB. If the measured value is
incorrect, this indicates the Rx path is broken or has defects.
For the maximum allowed receive signal level at the antenna port, refer to the LISA-C200 datasheet [1].
A Signal Generator should be connected to the Ant port when this test is performed.
If a unmodulated signal from a signal generator is used, a 30KHz offset should be applied to the signal
generated relative to the measurement channel. Without the offset, the majority of signal may not be
measured because the zero-IF direct down coversion receiver ignores the center of the channel component,
since the center frequency becomes the DC value once down converted. Example: If you measure a receive
channel #384 at 881.52 MHz (band class 0), then set the signal generator at 881.49 MHz or 881.55 MHz.
If you set the signal generate at 881.52 MHz, then utest may not read the expected RF level at the antenna
port.
3.4.5
AT+UTEST=3
The AT+UTEST=3 command sets the module to RF power emission ignoring the CDMA protocol.
This emission can generate interference that is prohibited by law in some countries. The use of
this feature is only intended for testing purposes in controlled environments by qualified users,
and must not be used during normal module operation. Follow the instructions provided in u-
blox documentation. U-blox assumes no responsibilities for the inappropriate use of this feature.
RF signal transmission can be triggered with this command:
AT+UTEST=3,<par1>,<par2>,<par3>,<par4>,<par5>
<par1>,…<par5> are command parameters that can be optionally set. If not set, the default value is used for
each parameter. For more AT commands details, see
u-blox C2 series AT Commands Manual
OK response will be sent after a time interval when the transmitter is turned off. After the OK response, any
other test command can be sent.
3.4.5.1
<par1>: Channel
For testing in CDMA network, the channel number is configured by <par1> according to +UTEST AT command
syntax. The channel numbers can be the same on two different bands, but +UTEST has an internal logic which
along with <par3> calculates the frequency at which the module transmits CDMA signal
The output is a modulated signals that occupies a 1.25MHz bandwidth around the center of the channel
