| US 7,519,135 B2 | ||
| Direct radio frequency (RF) sampling with recursive filtering method | ||
| Robert B. Staszewski, Garland, Tex. (US); Khurram Muhammad, Richardson, Tex. (US); Kenneth J. Maggio, Dallas, Tex. (US); and Dirk Leipold, Plano, Tex. (US) | ||
| Assigned to Texas Instruments Incorporated, Dallas, Tex. (US) | ||
| Filed on Jul. 08, 2002, as Appl. No. 10/190,867. | ||
| Claims priority of provisional application 60/312602, filed on Aug. 15, 2001. | ||
| Claims priority of provisional application 60/313772, filed on Aug. 20, 2001. | ||
| Claims priority of provisional application 60/348902, filed on Oct. 26, 2001. | ||
| Prior Publication US 2003/0035499 A1, Feb. 20, 2003 | ||
| Int. Cl. H03K 5/01 (2006.01) | ||
| U.S. Cl. 375—346 | 32 Claims |

| 24. A radio receiver comprising:
a radio frequency (RF) input to receive RF signals;
a sampling mixer coupled to the RF input to produce a discrete-time sample stream, and the sampling mixer comprising:
a history capacitor and a rotating capacitor, both coupled to a radio frequency (RF) input, the history and rotating capacitors
to integrate an RF current provided by the RF input to produce a charge on the history and rotating capacitors;
a read-out circuit coupled to the history and rotating capacitors, the read-out circuit to measure the charge on the rotating
capacitor;
a timing circuit coupled to the history and rotating capacitors and the read-out circuit, the timing circuit to produce clock
signals to control the operation of the history and rotating capacitors and the read-out circuit;
a clock activity detector coupled to the history and rotating capacitors, the clock activity detector containing circuitry
to predict an occurrence of a noise glitch;
a sample predictor coupled to the clock activity detector and the mixer, the sample predictor containing circuitry to predict
a value of discrete-time samples corrupted by the digital noise;
a delay unit coupled to the mixer, the delay unit containing circuitry to insert a delay of a duration at least equal to a
duration of the digital noise into the discrete-time sample stream;
a multiplexer coupled to the delay unit, the sample predictor, and the clock activity detector, the multiplexor to selects
between the outputs of the sample predictor and the delay unit; and
the radio receiver further comprising a signal processing unit coupled to the mixer, the signal processing unit containing
circuitry to process the output of the sampling mixer and create user usable data.
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