| 摘要 |
<p>The invention relates to a sigma-delta N-phase keying modulator having non-uniform polar quantisation. According to one embodiment of the invention, a quantiser produces a quantised output so that it represents a symbol, selected from a set of N symbols, depending on to which of the N non-symmetric cells, covering the complex plane in a non-overlapping manner, the phase of said symbol belongs. This may reduce the occurrence of larger phase transitions, which may lead to increased efficiency. The selection of non- symmetric cell boundaries may also affect the noise shaping spectrum of a sigma-delta N-PSK modulator. The invention also relates to an N-phase keying modulation method and a mobile telephone or transmitter including the modulator described above.</p> |
