Digi International Inc.

Maxstream, Inc.

David C Steed, Jr

Martin R Johnson

Hugh C Nielsen

Jeremy P Willden

A multi-channel superheterodyne receiver employs a low intermediate frequency (IF) and both high-side injection and low-side injection of a selected local oscillator (LO) signal into the mixer in order to position image frequencies outside the passband of a single image reject filter. Any channel that falls within a used portion of the image reject filter passband can be downconverted with image rejection if the utilized bandwidth portion is no greater than about 4 times the IF minus the bandwidth of a channel in the filter passband. Low side injection is used for channels falling within the lower half of the passband of the image reject filter, while high-side injection is used for channels falling within the upper half thereof. The image always remains outside the passband and the receiver can accommodate a greatly increased number of channels.

Superheterodyne receiver having at least one downconversion stage empolying a single image reject filter stage and both low-side injection and high-side injection of a local oscillator signal

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American Fork, UT, United States of America

David C Steed, Jr