**5.1.3 SNA calibration at limit level**

198 Wireless Communications and Networks – Recent Advances

gogi2000 TRC-SNA Specification

The SNA option shown in Figure 26 can also provide the De-Sense Measurement function. The software provides the Base-Station simulator, and provides VSG for WWAN and GPS measurement. The hardware provides switch and combiner for testing signal condition

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Fig. 25. Test configuration and system noise measured with WWAN card.

1800 GSM (200 kHz BW) AVG NOISE WHITE S/T

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**dBm**

Fig. 26. The SNA test configuration.

Since the WWAN or LTE cards are not originally designed for the noise measurement, and these cards need to provide about 60dB dynamic range for receiver. Therefore the variablegain amplifier must be utilized for AGC purpose at the same time when the noise floor of receiver reaches up to 6dB. SNA is here designed to measure the platform noise. The dynamic range of receiver is from 4dB under limit line level up to 16dB above limit line level. With front end LNA implemented, the noise floor of SNA system is around 2dB and the average noise floor level is 4dB lower than that of WWAN or LTE card.

The noise floor level for WWAN is -115dBm. However, the limit line level for some particular applications like identifying the main noise source (system noise or panel noise) will be -114dBm. We can use the receiver with -115dBm noise floor level to receive the noise with level of -114dBm, and there is 1dB uncertainty for signal to noise level result. Since the average noise floor level can be obtained for SNA is -119dBm, it can provide more accurate signal to noise ratio for -114dBm measurement in general cases as in Figure 27.

Fig. 27. Noise floor level obtained for SNA.
