US 5,280,636 A · Multi-band digital receiving apparatus and method with bandwidth reduction

Abstract

Multiple simultaneous uses of a multi-service digital receiver are made possible with a single practical analog-to-digital converter by translating the various service bands in frequency to form a single, generally continuous composite service band in which substantial frequency gaps between the different services are eliminated. Bandwidth requirements are further reduced by a bandfolding technique in which at least one service waveband is divided about an intermediate mixing frequency, the divided portions are overlapped so that they collectively occupy a sub-waveband with a smaller bandwidth than the original band, and the mixing frequency is chosen such that user-selected frequencies do not interfere with other active frequencies. Interference between non-selected active frequencies is permissible and simply ignored.

Claims24

Dependent claims

A method of reducing the effective bandwidth of a waveband of electromagnetic communications frequencies without reducing its signal carrying capacity, said waveband having a plurality of discrete and mutually spaced active frequencies from which at least one desired frequency may be selected, comprising:

dividing said waveband into multiple portions,
selecting said waveband portions so that said desired frequencies do not interfere with the remainder of said active frequencies, and
overlapping said waveband portions so that they collectively occupy a sub-waveband with a smaller bandwidth than said waveband.

A receiver for a plurality of individual electromagnetic communications wavebands that are mutually spaced along the electromagnetic spectrum, comprising:

means for translating at least some of said wavebands in frequency so that said wavebands form a single generally continuous composite waveband having a bandwidth substantially less than the aggregate bandwidth of said individual wavebands prior to translation, said translating means comprising respective oscillators for mixing the signals within each of said individual wavebands with respective oscillation signals, wherein the frequencies of said oscillation signals are selected to establish said frequency translations,
a single analog-to-digital converter connected to convert received analog signals within said composite waveband to digital format, and
digital tuning means for selecting at least one desired reception frequency from said digitized composite waveband.

Dependencies are inferred from the claim text.

Multi-band digital receiving apparatus and method with bandwidth reduction

Life of this patent

Multi-band digital receiving apparatus and method with bandwidth reduction

Life of this patent

Abstract

Claims24