Simplified high frequency tuner and tuning method

• US 8,467,761 B2
• Filed: 11/28/2012
• Issued: 06/18/2013
• Est. Priority Date: 09/13/1996
• Status: Expired due to Fees

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Suominen, Edwin A.
• Primary Examiner(s): Jackson, Blane J
• Application Number:
  US13/687,160
• Publication Number:
  US 20130095778A1
• Time in Patent Office: 202 Days
• Field of Search: 455/296, 455/307, 455/323, 455/324, 455/333, 455/339
• US Class Current: 455/307
• CPC Class Codes: H03D 3/007 by converting the oscillations into two quadrature related signals H03D3/245 takes precedence
• CPC Class Codes: H03D 3/009 Compensating quadrature phase or amplitude imbalances
• CPC Class Codes: H03D 7/165 at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature combined with amplitude demodulation H03D1/2245, combined with angle demodulation H03D3/007; N-path filters H03H19/002
• CPC Class Codes: H04B 1/06 Receivers
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/16 Circuits
• CPC Class Codes: H04B 1/26 for superheterodyne receivers multiple frequency-changing H03D7/16
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22
• CPC Class Codes: H04L 25/067 providing soft decisions, i.e. decisions together with an estimate of reliability H04L25/068 and H04L25/069 take precedence; sequence estimation techniques H04L25/03178

Abstract

A disclosed method tunes a signal from a channelized spectrum having a predetermined channel spacing. A signal of interest having a predetermined maximum bandwidth is mixed with a local oscillator signal, which has a frequency that is an integer multiple of the channel spacing or one-half of a channel spacing displaced from an integer multiple of the channel spacing. The local oscillator signal is selected to frequency translate the signal of interest to within a near-baseband passband whose lower edge is spaced from DC by at least about the maximum bandwidth of the signal of interest. Problems associated with 1/f noise, DC offsets, and self-mixing products are avoided or substantially diminished. Other methods and systems are also disclosed.

Claims

1. A mobile radio device having an integrated RF receiver that tunes a radio channel from a signal spectrum that includes a plurality of radio channels, comprising:

a channel tuning interface;

a demodulated signal output interface, and

an integrated RF receiver coupled to the channel tuning interface and the demodulated signal interface, the RF receiver comprising;

a mixer coupled to receive the signal spectrum and a mixing signal as inputs and having a low-IF signal as an output, wherein the low-IF signal is within a near-baseband passband sized to fit one radio channel and the lower edge of which is spaced from DC by at least about 20 KHz;

local oscillator (LO) generation circuitry coupled to receive a radio channel tuning control as an input and configured to provide an oscillation signal, the oscillation signal being dependent upon the radio channel tuning control and being used to generate the mixing signal for the mixer;

quadrature generation circuitry configured to receive the mixing signal from the LO generation circuitry and to generate two phase shifted mixing signals for use by the mixer;

low-IF conversion circuitry coupled to receive the low-IF signals from the mixer and configured to output digital signals, the low-IF conversion circuitry including first and second analog-to-digital converters coupled to the real and imaginary low-IF signals and configured to output real and imaginary digital signals;

a digital-signal-processor (DSP) coupled to receive the digital signal from the low-IF conversion circuitry and configured to demodulate the signal modulation within the selected radio channel, to digitally tune the selected radio channel, and to output a digital signal, the DSP comprising an on-chip, general purpose, digital processor, and

circuitry coupled to receive the digital signal from the DSP and configured to output the demodulated signal;

wherein the mixer, the LO generation circuitry, the low-IF conversion circuitry, and the DSP including the frequency control circuitry are integrated within a single integrated circuit;

wherein the integrated circuit is made using a single-chip low-power implementation process.

2. An integrated radio receiver that tunes a selected radio channel from a channelized spectrum containing a plurality of radio channels, comprising:

mixer circuitry coupled to receive an RF signal spectrum and phase shifted mixing signals as inputs and having real and imaginary low-IF signals as output, wherein the low-IF signals are within a near-baseband passband sized to fit one radio channel and the lower edge of which is spaced from DC by at least about 20 KHz;

local oscillator (LO) generation circuitry configured to provide an oscillation signal, the oscillation signal being dependent upon the frequency of the selected radio channel and being used to generate the phase shifted mixing signals for the mixer circuitry;

low-IF conversion circuitry coupled to receive the real and imaginary low-IF signals from the mixer circuitry and configured to output digital signals, the low-IF conversion circuitry including first and second analog-to-digital converters coupled to the real and imaginary low-IF signals and configured to output real and imaginary digital signals; and

digital-signal-processor (DSP) circuitry coupled to receive the digital signals from the low-IF conversion circuitry and configured to demodulate the selected radio channel, to digitally tune the selected radio channel, and to output demodulated signals; and

wherein the mixer circuitry, the LO generation circuitry, the low-IF conversion circuitry, and the DSP circuitry are integrated within a single integrated circuit.

3. A method for tuning a selected radio channel from a channelized spectrum containing a plurality of channels, in an integrated receiver, comprising:

generating an oscillation signal, the oscillation signal being dependent upon the frequency of the selected channel;

providing phase shifted mixing signals based upon the oscillation signal;

mixing an RF input signal spectrum with the phase shifted mixing signals to generate real and imaginary low-IF output signals, wherein the real and imaginary low-IF output signals are within a near-baseband passband sized to fit one channel and the lower edge of which is spaced from DC by at least about 20 KHz;

converting the low-IF output signals to real and imaginary digital signals; and

processing the digital signals utilizing digital signal processing (DSP) circuitry to demodulate the selected radio channel, to digitally tune the selected radio channel, and to output demodulated signals;

wherein the generating, providing, mixing, converting, processing and converting steps are performed within a single integrated circuit.