Multi-stage digital RF translator

• US 5,490,173 A
• Filed: 07/02/1993
• Issued: 02/06/1996
• Est. Priority Date: 07/02/1993
• Status: Expired due to Term

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Ford Motor Company
• Inventors: Wargnier, James A., Whikehart, J. William
• Primary Examiner(s): TSE, YOUNG TOI
• Application Number:
  US08/084,903
• Time in Patent Office: 949 Days
• Field of Search: 375/316, 375/324, 375/328, 375/340, 375/343-345, 375/350, 364/724.1, 364/724.13, 329/315, 329/318, 455/307, 370/70
• US Class Current: 375/316
• CPC Class Codes: H03D 2200/005 Analog to digital conversion
• CPC Class Codes: H03D 2200/0056 including a digital decimation filter
• CPC Class Codes: H03D 2200/006 Signal sampling
• CPC Class Codes: H03D 2200/0076 using a distributed mixer
• CPC Class Codes: H03D 7/00 Transference of modulation from one carrier to another, e.g. frequency-changing H03D9/00, H03D11/00 take precedence; dielectric amplifiers, magnetic amplifiers, parametric amplifiers used as a frequency-changers H03F
• CPC Class Codes: H03D 7/166 using two or more quadrature frequency translation stages
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04B 1/0021 Decimation, i.e. data rate reduction techniques H04B1/0025 takes precedence
• CPC Class Codes: H04B 1/26 for superheterodyne receivers multiple frequency-changing H03D7/16

Abstract

An apparatus for performing digital signal frequency translation in a digital receiver is disclosed. The apparatus uses a plurality of mixer-filter-decimator stages for performing the digital signal frequency translation. The translation function converts the digital signal to an intermediate frequency (IF), where such translation is distributed among the plurality of mixer-filter-decimator stages to thereby simplify the mixing requirements.

Claims

1. An apparatus for performing digital signal frequency translation, comprising:

a mixer-filter-decimator stage comprising mixing means for translating a digital signal to an intermediate frequency signal, filter means for low-pass filtering said intermediate frequency signal and decimation means for lowering a rate of said filtered intermediate frequency signal; and

multiplexing means having an output coupled to said mixing means and an input coupled to said decimation means for implementing a multi-stage digital frequency translator using a single mixer-filter-decimator stage.

2. The apparatus of claim 1, further comprising a passband filter coupled to said decimation means to provide passband ripple correction.

3. A digital receiver, comprising

an RF amplifier configured to receive and amplify an RF signal from an antenna;

an analog-to-digital converter configured to convert said amplified RF signal to a digital signal;

a mixer-filter-decimator stage comprising mixing means for translating said digital signal to an intermediate frequency signal, filter means for low-pass filtering said intermediate frequency signal and decimation means for lowering a rate of said filtered intermediate frequency signal; and

multiplexing means having an output coupled to said mixing means and an input coupled to said decimation means for implementing a multi-stage digital frequency translator using a single mixer-filter-decimator stage.

4. The receiver of claim 3, further comprising tuning means coupled between said antenna and said RF amplifier for selecting a carrier frequency from said RF signal.

5. The receiver of claim 3, further comprising a passband filter coupled to said decimation means to provide passband ripple correction.