AN-1434
AN-1434 is Crest Factor Invariant RF Power Detector manufactured by National Semiconductor.
Overview of Digital Modulation in Cellular Phones
A digital modulation scheme is more spectral efficient if it can transmit a greater amount of data or bits per second in a given bandwidth. Therefore, we define the bandwidth or spectral efficiency of a modulation to be “transmission bit rate divided by the occupied channel bandwidth, bit/second/ Hz.” Table 1 indicates that a higher M-ary modulation scheme has a large number of output levels and, therefore, has better spectral efficiency.
TABLE 1. Theoretic Bandwidth Efficiency Modulation Scheme GMSK QPSK 8PSK 16QAM Figure 1 shows the constellation...
