Input IP3 -8.7 dBm the signal chain must be analyzed. The analysis of spu- rious performance is a little bit more difficult but can Output IP3 +21.3 dBm nonetheless be analyzed. In analyzing the CDMA2000 specifications, there are two specifications to review. The Given this signal chain, the SNR can now be de- key specifications are the two-tone blocking and single- termined for the reference sensitivity on p. 170. Using tone blocking tests. Antenna Filter Filter NF=1 dB NF= 1.7 dB NF=1 dB NF=1.7 dB NF=12 dB Gain=-1 dB Gain= 15 dB Gain=-1 dB Gain=15 dB Gain=3 dB IP3= 1000 dB IP3= 29 dB IP3=1000 dB IP3=29 dB IP3=26 dB Rake & Decode Filter Filter NF=2 dB NF=8 dB NF=7 dB NF=5 dB NF=28 dB Gain=-2 dB Gain=8 dB Gain=14 dB Gain=-5 dB Gain=0 dB IP3= 1000 dB IP3=28 dB IP3=30 dB IP3=1000 dB IP3=45 dB Figure 2.3-15 SDR receive signal chain. CHAPTER 2.3 Software defined radio Two-tone blocking requires that the receiver tolerate single-tone performance can be calculated with reference two CW carriers at -45 dBm. Since this is an IF sampling to -30 dBm, giving -78.9 dBc. Since the ADC perfor- application, the even-order term (difference) falls near mance is listed at -95 dBc for either single or two tones, DC and is filtered. The odd-order products are the most no performance limitations should be anticipated. critical, especially the third-order products that fall UMTS is a little different. First, there is no single-tone in-band. In Figure 2.3-16, a third-order term (2f1-f2) is desensitization specification. Thus the primary specifi- shown to fall near the channel center of the CDMA cation is the intermodulation testing. This too is different channel. Since it falls near the channel center, it cannot because only one of the tones is CW; the other is be allowed to disrupt the desired CDMA carrier. The a modulated CDMA carrier. Therefore, when 2f1-f2 is goal is to determine how large the intermodulation generated, it is an image of the CDMA signal shifted by product can be such that disruption does not occur. the difference b