Impulse-scanned n-path filter for several frequency ranges

Claim 2

A double super heterodyne receiver arrangement for receiving a plurality of frequency bands, said radio receiver comprising: a first frequency band receiving channel including an intermediate frequency stage; a second frequency band receiving channel; an N-path filter means operating as a second intermediate frequency stage further comprising: a. an N-path input lead; b. an N position switching means connected to said input and having an output; c. N low pass filters connected to each of said N position switching means outputs; d. a second N position switching means connected to said N low pass filters, said second switching means switching said N low pass filter outputs to one output path, said output path being the output lead of said N-path filter; e. an impulse generator means for causing said switching means to scan said N-paths, the frequency of said impulse generator means being equal to a lower harmonic of the center frequency of the received frequency bands of the receiver arrangement; a switching means connected to said N-path filter input lead for switching between the said first and second frequency band receiving channels; and a band pass filter means connected to the output lead of said Npath filter.

Claim 3

A double super heterodyne receiver arrangement for receiving a plurality of frequency bands, said radio receiver comprising: a first frequency band receiving channel including an intermediate frequency stage; a second frequency band receiving channel; an N-path filter means operating as a second intermediate frequency stage further comprising: a. an N-path input lead; b. an N position switching means connected to said input and having an output; c. N low pass filters connected to each of said N position switching means outputs; d. a second N position switching means connected to said N low pass filters, said second switching means switching said N low pass filter outputs to one output path, said output path being the output lead of said N-path filter; e. an impulse generator means for causing said switching means to scan said N-paths, the frequency of said impulse generator means being equal to a lower harmonic of the center frequency of the received frequency bands of the receiver arrangement; a switching means connected to said N-path filter input lead for switching between the said first and second frequency band receiving channels; and a band pass filter means connected to the output lead of said N-path filter.

Claim 4

A double super heterodyne receiver arrangement for receiving a plurality of frequency bands, said radio receiver comprising: a first frequency band receiving channel including an intermediate frequency stage; a second frequency band receiving channel; an N-path filter means operating as a second intermediate frequency stage further comprising: a. an N-path input lead; b. an N position switching means connected to said input and having an output; c. N low pass filters connected to each of said N position switching means outputs; d. a second N position switching means connected to said N low pass filters, said second switching means switching said N low pass filter outputs to one output path, said output path being the output lead of said N-path filter; e. an impulse generator means for causing said switching means to scan said N-paths, the frequency of said impulse generator means being equal to a lower harmonic of the center frequency of the received frequency bands of the receiver arrangement; a switching means connected to said N-path filter input lead for switching between the said first and second frequency band receiving channels; and a band pass filter means connected to the output lead of said N-path filter.

Claim 5

A receiver according to claim 1 wherein said band pass filter means has a pass band which is an integral fraction for a multiple of the received frequency bands.