| US 7,551,694 B2 | ||
| Limiter based analog demodulator | ||
| Zhongxuan Zhang, Fremont, Calif. (US); Lixin Zhao, Shanghai (China); and Steve Xuefeng Jiang, Fremont, Calif. (US) | ||
| Assigned to Marvell World Trade Ltd., St. Michael (Barbados) | ||
| Filed on Jan. 19, 2006, as Appl. No. 11/307,015. | ||
| Claims priority of provisional application 60/645847, filed on Jan. 20, 2005. | ||
| Prior Publication US 2007/0189420 A1, Aug. 16, 2007 | ||
| Int. Cl. H04L 27/14 (2006.01) | ||
| U.S. Cl. 375—326 [375/322; 375/354; 375/316; 375/229; 375/371; 375/225; 370/503; 370/442; 370/354; 348/614; 348/607] | 4 Claims |

| 2. A limiter based demodulator comprising:
a power amplifier receiving a base-band signal;
a local clock operating at a base-band frequency;
a first multiplier receiving an output from the power amplifier and the local clock to provide an in phase signal;
a quadrature phase shifter receiving the local clock;
a second multiplier receiving the output from the power amplifier and an output from the quadrature phase shifter to provide
a quadrature signal;
a first analog filter receiving the in phase signal;
a second analog filter receiving the quadrature signal;
a first analog to digital converter connected to the first analog filter and providing a digitized in phase signal;
a second analog to digital converter connected to the second analog filter and providing a digitized quadrature signal; and
a phase detector that receives the digitized in phase and quadrature signals and includes:
a hardware accelerator receiving the digitized in phase and quadrature signals, the hardware accelerator including:
means for filtering and decimating the digitized in phase and quadrature signals to three times symbol rate;
a Burst Sync means and a TDMA means receiving the filtered and decimated signals to generate a slot timing signal;
a storage register responsive to the slot timing signal;
a DSP processor receiving signals from the storage registers, the DSP processor including:
a Clock Recovery means for estimating a timing offset;
an Interpolator means to perform timing adjustment and 3 to 2 rate conversion based on the timing offset;
an ArcTan means to convert the in phase and quadrature signals into a phase signal;
a Carrier Recovery means to perform carrier offset adjustment of the phase signal; and
Decoder means to perform final decoding of the phase signal.
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