Adjusting untrimmed VCO during operation of the oscillator

• US 6,509,806 B2
• Filed: 06/20/2001
• Issued: 01/21/2003
• Est. Priority Date: 01/18/2000
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Andrews, Joseph
• Primary Examiner(s): LAM, TUAN THIEU
• Application Number:
  US09/887,227
• Publication Number:
  US 20010035796A1
• Time in Patent Office: 580 Days
• Field of Search: 331/107.R, 331/108.R, 331/109, 331/117.R, 331/117.FE, 331/110, 331/111
• US Class Current: 331/117.00R
• CPC Class Codes: H03B 5/1203 the amplifier being a single transistor
• CPC Class Codes: H03B 5/1231 the amplifier comprising one or more bipolar transistors
• CPC Class Codes: H03B 5/1243 the means comprising voltage variable capacitance diodes
• CPC Class Codes: H03C 1/36 by means of semiconductor device having at least three electrodes H03C1/34, H03C1/50, H03C1/52, H03C1/62 take precedence
• CPC Class Codes: H03J 2200/29 Self-calibration of a receiver
• CPC Class Codes: H03L 2207/06 Phase locked loops with a controlled oscillator having at least two frequency control terminals
• CPC Class Codes: H03L 7/099 concerning mainly the controlled oscillator of the loop
• CPC Class Codes: H03L 7/18 using a frequency divider or counter in the loop H03L7/20, H03L7/22 take precedence

Abstract

A frequency oscillator tuning process at the manufacturing stage is replaced with an adjustment of a resonant circuit in the frequency oscillator during an operation of the oscillator. The adjustment utilizes a crystal oscillator, a frequency oscillator such as a voltage-controlled oscillator (VCO), and a trimmer in a phase-locked loop configuration to determine a correction voltage required for an untrimmed VCO to operate at a nominally specified frequency by adjusting an input tuning voltage for a resonant circuit.

Claims

1. An input voltage tuner for a frequency oscillator, comprising:

a first circuit configured to receive an input tuning signal for the oscillator;

a look-up table which provides a correction value corresponding to said input tuning signal;

a processor operating to control the look-up table during operation of the oscillator, such that the oscillator operates at a nominally specified output frequency;

a second circuit configured to convert said correction value into a form operable by a variable transistor output load; and

said variable transistor output load, coupled to a collector of a first transistor, configured to receive the converted correction value from the second circuit and provide frequency pulling where the particular frequency is fine tuned to the nominally specified output frequency of the oscillator.

2. The tuner of claim 1, wherein said first and second circuits are an analog to digital converter and a digital to analog converter, respectively.