| abstract |
A digital receiver, for example for digital terrestrial systems, comprises an analognsingle-conversion zero intermediate frequency down-converter 12. The down-convertern12 is of the quadrature type and produces quadrature baseband signals I and Q of thendesired RF channel. Digital-analog converters 18, 19 convert the baseband I and Qnsignals into the digital domain, where they are up-converted to near zero intermediatenfrequency by an up-converter 24, 25, 26, 27,28 and demodulated by the demodulatorn29. Quadrature balance which may be degraded in the down-converter 12 is restored innthe up-converter 24-28 by means of a phase adjuster 27 which is controlled by annalgorithm 33 which monitors bit rate errors at various points in the demodulator 29. |