Digital demodulator arrangement for quadrature signals
AssigneeStc PLC
InventorIan A. W. Vance
Life of this patent
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Abstract
A direct conversion receiver in which the quadrature I and Q signals are converted into pulse density modulated digital data streams by delta-sigma modulators 14, 15. The resultant digital data streams are then processed in a logic block 18 according to predetermined logic truth tables. The digital output of the processor 18 is then converted back to an analogue signal.
Claims4
A direct conversion radio receiver comprising means for receiving a modulated carrier frequency signal and for converting the signal to in-phase and quadrature-phase baseband signals;
- a pair of analog-to-digital conversion means connected to said receiving means for converting the in-phase and quadrature-phase signals into respective pulse density modulated (PDM) digital data streams;
- and logic means coupled to said pair of conversion means and responsive to said pulse density modulated digital data streams for providing a demodulated output signal.
A method of demodulating a pair of related in-phase and quadrature-phase signals provided by a zero I.F. or direct conversion radio receiver comprising analog-to-digital converting each of said in-phase and quadrature-phase signals into respective pulse density modulated (PDM) digital data streams;
- and logically processing said pulse density modulated digital data streams in accordance with a predetermined table of input logic conditions to provide a demodulated output signal.
Dependencies are inferred from the claim text.