Receiver tuning system

• US 6,751,445 B2
• Filed: 12/30/2002
• Issued: 06/15/2004
• Est. Priority Date: 03/18/1997
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kasperkovitz, Wolfdietrich G., Vaucher, Cicero S.
• Primary Examiner(s): Nguyen, Lee
• Application Number:
  US10/331,276
• Publication Number:
  US 20030134609A1
• Time in Patent Office: 533 Days
• Field of Search: 455/76, 455/77, 455/258, 455/259, 455/260, 455/265, 455/165.1, 455/173.1, 455/178.1, 455/180.3, 455/183--18, 455/192--19, 331/2, 331/11, 331/14, 331/16, 331/18, 331/25, 375/376
• US Class Current: 455/76
• CPC Class Codes: H03J 1/005 in a loop
• CPC Class Codes: H03L 7/187 using means for coarse tuning the voltage controlled oscillator of the loop H03L7/191 - H03L7/195 take precedence
• CPC Class Codes: H03L 7/23 with pulse counters or frequency dividers

Abstract

In a receiver, a frequency-synthesis circuit (SYNTH) generates a stepped-frequency signal (Ssf) having a frequency which can be varied in steps. A synchronization circuit (LOOP) synchronizes a tuning oscillator (LO) with the stepped-frequency signal (Ssf). It provides an integer frequency-relationship between the stepped-frequency signal (Ssf) and the tuning oscillator (LO). That is, if the stepped-frequency signal (Ssf) has a frequency Fsf, the tuning oscillator (LO) will operate at a frequency Flo=N·Fsf, N being an integer or an integer fraction.

Claims

1. A receiver comprising a tuning system for tuning the receiver, the tuning system comprising:

a frequency-synthesis circuit for generating a stepped-frequency signal having a frequency varying in steps with a step size; and

a synchronization circuit for synchronizing a tuning oscillator with the stepped-frequency signal to form a tuning frequency varying with tuning steps, said synchronization circuit comprising means for providing an adjustable integer frequency relationship between the stepped-frequency signal and the tuning oscillator,

characterized in that the frequency-synthesis circuit comprises means, coupled to said synchronization circuit, for varying the step size of the stepped-frequency signal in response to the adjustable integer-frequency relationship such that the tuning steps of the tuning frequency formed by the synchronization circuit are substantially uniform despite any changes in the adjustable integer-frequency relationship by said providing means.

2. A receiver as claimed in claim 1, characterized in that the synchronization circuit has a bandwidth covering at least a substantial portion of a typical baseband associated with a type of transmission signal processable by the receiver.

3. A receiver as claimed in claim 1, characterized in that the synchronization circuit includes a phase/frequency detector for providing a frequency control signal to the tuning oscillator as a function of a synchronization error between the stepped-frequency signal and the tuning oscillator.

4. A receiver as claimed in claim 3, characterized in that the relation between the frequency control signal and the synchronization error is adjustable.

5. A tuning system comprising:

a frequency-synthesis loop for generating a stepped-frequency signal having a frequency varying in steps with a step size; and

a synchronization circuit for synchronizing a tuning oscillator with the stepped-frequency signal to form a tuning frequency varying with tuning steps, said synchronization circuit comprising means for providing an adjustable integer frequency-relationship between the stepped-frequency signal and the tuning oscillator,

characterized in that the frequency-synthesis circuit comprises means, coupled to said synchronization circuit, for varying the step size of the stepped-frequency signal in response to the adjustable integer-frequency relationship such that the tuning steps of the tuning frequency formed by the synchronization circuit are substantially uniform despite any changes in the adjustable integer-frequency relationship by said providing means.

6. A method of tuning comprising the steps:

generating a stepped-frequency signal having a frequency varying in steps with a step size;

synchronizing a tuning oscillator to the stepped-frequency signal to form a tuning frequency with tuning steps; and

providing an adjustable integer frequency-relationship between the stepped-frequency signal and the tuning frequency, characterized in that the method of tuning further comprises the step;

varying the step size of the stepped-frequency signal in response to the adjustable integer-frequency relationship such that the tuning steps of the tuning frequency are substantially uniform despite any changes in the adjustable integer-frequency relationship.