Low power digital receiver

• US 4,910,752 A
• Filed: 02/29/1988
• Issued: 03/20/1990
• Est. Priority Date: 06/15/1987
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Gailus, Paul H., Turney, William J., Yester, Francis R. Jr.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Chin, Stephen
• Application Number:
  US07/161,950
• Time in Patent Office: 750 Days
• Field of Search: 375/75, 375/94, 375/97, 375/121, 455/31, 455/36, 455/343, 455/196, 455/257, 340/331, 340/311, 328/140
• US Class Current: 375/316
• CPC Class Codes: H03J 5/0281 the digital values being held in an auxiliary non erasable memory
• CPC Class Codes: H04B 1/1615 Switching on; Switching off, e.g. remotely battery saving circuits associated with selective call operation H04W52/00; details of power consumption reduction in a PLL, H03L7/0802, H03L7/14, H03L2207/08, H03L2207/18; muting amplifiers by gain control see H03G3/34
• CPC Class Codes: H04W 52/0293 having a sub-controller with a low clock frequency switching on and off a main controller with a high clock frequency
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A low power digital receiver (10) is provided that contemporaneously selects the lowest possible sampling signal frequency (34) (from a plurality of available sampling signals), and received signal level (28) to properly digitize (32) and recover a desired signal. Digitization is performed after the first IF using broadband stages (28, 30, and 32) that are temporarily enabled (44) to rapidly digitize the first IF signal. This, together with the low sampling rate, minimizes the power consumption of the receiver (10) thereby permitting portable and mobile digital receiver embodiments.

Claims

1. A method for recovering an information signal with a low power digital receiver, comprising the steps of:

(a) bandlimiting a received signal to provide a bandlimited signal;

(b) converting said bandlimited signal to provide an intermediate frequency signal;

(c) filtering said intermediate frequency signal to provide a filtered signal;

(d) generating at least two sampling signals;

(e) selecting a particular one of said at least two sampling signals in response to a control signal;

(f) sampling and digitizing said filtered signal using said selected one of said at least two sampling signals to provide a digitized signal;

(g) processing said digitized signal to recover the information signal, and for generating said control signal in response to predetermined characteristics of said digitized signal such that the sampling rate is dynamically varied to properly recover the information signal while maintaining the lowest allowable sampling frequency thereby minimizing the power consumption of the receiver.

2. A low power digital receiver for recovering an information signal, comprising:

means for bandlimiting a received signal to provide a bandlimited signal;

means for converting said bandlimited signal to provide an intermediate frequency signal;

means for filtering said intermediate frequency signal to provide a filtered signal;

means for generating at least two sampling signals;

means for selecting a particular one of said at least two sampling signals in response to a control signal;

means for sampling and digitizing said filtered signal using said selected one of said at least two sampling signals to provide a digitized signal; and

means for processing said digitized signal to recover the information signal, and for generating said control signal in response to predetermined characteristics of said digitized signal such that the sampling rate is dynamically varied to properly recover the information signal while maintaining the lowest allowable sampling frequency thereby minimizing the power consumption of the receiver.

3. A method for recovering an information signal with a low power digital receiver, comprising the steps of:

(a) bandlimiting a received signal to provide a bandlimited signal;

(b) converting said bandlimited signal to provide an intermediate frequency signal;

(c) filtering said intermediate frequency signal to provide a filtered signal;

(d) generating at least two sampling signals;

(e) selecting a particular one of said at least two sampling signals in response to a control signal;

(f) sampling said filtered signal using said selected one of said at least two sampling signals to provide a sampled signal having a frequency approximately one-fourth that of said selected sampling signal;

(g) digitizing said sampled using said selected one of said sampling signals to provide a digitized signal;

(h) processing said digitized signal to recover the information signal, and for generating said control signal in response to predetermined characteristics of said sampled signal and said digitized signal such that the sampling rate is dynamically varied to properly recover the information signal while maintaining the lowest allowable sampling frequency thereby minimizing the power consumption of the receiver.