Patent EP0143539A2 successfully refreshed from Google Patents.
EP0143539A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Digital demodulator arrangement for quadrature signals
Assignee: STC PLC
•
Filing: 1984-10-15
•
Granted: —
•
Expires: 2004-10-15
Abstract
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.
Inventors
- 👤 Ian Alistair Ward Vance
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 09:02
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/007; H04; H04L; H04L27/00; H04L27/10; H04L27/14; H04L27/144; H04L27/152; H04L27/1525; H04L27/32; H04L27/34; H04L27/38; H03D2200/00; H03D2200/0041; H03D2200/005; H03D2200/0052; H03D3/006
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
133 words
A radio receiver having a first signal path in which a signal is mixed with a local oscillator frequency running at the main transmission frequency and then filtered to give a first mixed signal defined as an in-phase signal (I), a second signal path in which the received signal is mixed with the local oscillator frequency but with a relative phase shift and then filtered to give a second mixed signal defined as a quadrature signal (Q), characterised in that each signal path includes analogue-to-digital conversion means whereby the I and Q signals are converted into pulse density modulated (PDM) digital data streams respectively, the receiver also including a logic means to which the outputs of the PDM streams are applied, whereby the logic means output is a demodulation of the digital signals.
Claim 2
Dependent Claim
133 words
A radio receiver having a first signal path in which a signal is mixed with a local oscillator frequency running at the main transmission frequency and then filtered to give a first mixed signal defined as an in-phase signal (I), a second signal path in which the received signal is mixed with the local oscillator frequency but with a relative phase shift and then filtered to give a second mixed signal defined as a quadrature signal (Q), characterised in that each signal path includes analogue-to-digital conversion means whereby the I and Q signals are converted into pulse density modulated (PDM) digital data streams respectively, the receiver also including a logic means to which the outputs of the PDM streams are applied, whereby the logic means output is a demodulation of the digital signals.
Claim 3
Dependent Claim
21 words
A receiver according to claim 1 characterised in that the analogue-to-digital conversion means in each signal path comprises a delta-sigma modulator.
Claim 4
Dependent Claim
51 words
A receiver according to claim 1 characterised in' that the logic means includes look-up table means addressed by the.digital data and combinational logic wherein the output of the look-up operation is a binary weighted digital word defining the values of a sample of an analogue signal represented by the digital signals.
Claim 5
Independent Claim
57 words
A method of demodulating quadrature signals formed in a zero I.F. or direct conversion radio receiver characterised in that the quadrature signals are each analogue-to-digital converted into respective pulse density modulated digital data streams, the data streams being applied to a logic means arranged to process the signals according to a predetermined table of input logic conditions.
Claim 6
Independent Claim
57 words
A method of demodulating quadrature signals formed in a zero I.F. or direct conversion radio receiver characterised in that the quadrature signals are each analogue-to-digital converted into respective pulse density modulated digital data streams, the data streams being applied to a logic means arranged to process the signals according to a predetermined table of input logic conditions.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.