Up / down conversion circuitry for radio transceiver
First Claim
1. Down conversion circuitry for use in a radio transceiver for down converting a received RF information signal to a base band information signal in two stages wherein a first said stage converts said RF information signal to an IF information signal and a second said stage converts said IF information signal to said base band information signal, said down conversion circuitry comprising:
- (a) a mixer component configured for down converting said RF information signal to said IF information signal using an RF oscillator signal;
(b) an image rejection mixer component configured for down converting said IF information signal to said base band signal using an IF oscillator signal and achieving substantial image signal rejection; and
, (c) a frequency synthesizer configured for generating each of said RF and IF oscillator signals whereby said IF oscillator signal is an integer (N) sub-harmonic of said RF oscillator signal and the frequency value of said IF oscillator signal is pre-selected to be within the operating frequency band of said image rejection mixer component.
4 Assignments
0 Petitions
Accused Products
Abstract
A multi-channel RF receiver uses an image rejection mixer (e.g. double quadrature mixer) in the IF down conversion stage for image side band rejection (whereby use of an IF narrow band filter for image rejection may be omitted if desired) and comprises a simplified frequency synthesizer which generates both a “wandering” IF oscillator frequency and an RF oscillator frequency for the up/down conversion stages (being, for down conversion, from RF to IF and from IF to base band. The IF used for a particular RF carrier (channel) is selected so as to be both an integer (N) sub-harmonic of that RF carrier and within the operating frequency band of the image rejection mixer. Advantageously, the synthesizer comprises only one loop and one VCO, wherein the IF oscillator signal is produced from the RF oscillator signal by means of a frequency divider.
-
Citations
20 Claims
-
1. Down conversion circuitry for use in a radio transceiver for down converting a received RF information signal to a base band information signal in two stages wherein a first said stage converts said RF information signal to an IF information signal and a second said stage converts said IF information signal to said base band information signal, said down conversion circuitry comprising:
-
(a) a mixer component configured for down converting said RF information signal to said IF information signal using an RF oscillator signal;
(b) an image rejection mixer component configured for down converting said IF information signal to said base band signal using an IF oscillator signal and achieving substantial image signal rejection; and
,(c) a frequency synthesizer configured for generating each of said RF and IF oscillator signals whereby said IF oscillator signal is an integer (N) sub-harmonic of said RF oscillator signal and the frequency value of said IF oscillator signal is pre-selected to be within the operating frequency band of said image rejection mixer component. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A method for use in a radio transceiver for down converting, in two stages, a received RF information signal to a base band information signal wherein a first said stage converts said RF information signal to an IF information signal and a second said stage converts said IF information signal to said base band information signal, said method comprising:
-
(a) down converting said RF information signal to said IF information signal using an RF oscillator signal;
(b) down converting said IF information signal to said base band signal using image rejection down conversion means configured for achieving substantial image signal rejection, and an IF oscillator signal; and
,(c) generating each of said RF and IF oscillator signals whereby said IF oscillator signal is an integer (N) sub-harmonic of said RF oscillator signal, including preselecting the frequency value of said IF oscillator signal to be within the operating frequency band of said image rejection down conversion means. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
-
15. Up conversion circuitry for use in a radio transceiver for up converting, in two stages, a base- band information signal to an RF information signal for transmission, wherein a first said stage converts said base band information signal to an IF information signal and a second said stage converts said IF information signal to said RF information signal, said up conversion circuitry comprising:
-
(a) an image rejection mixer component configured for up converting said base band information signal to said IF information signal using an IF oscillator signal and achieving substantial image signal rejection;
(b) a mixer component configured for up converting said IF information signal to said RF information signal using an RF oscillator signal; and
,(c) a frequency synthesizer configured for generating each of said RF and IF oscillator signals whereby said IF oscillator signal is an integer (N) sub-harmonic of said RF oscillator signal and the frequency value of said IF oscillator signal is pre-selected to be within the operating frequency band of said image rejection mixer component. - View Dependent Claims (16, 17)
-
-
18. A method for use in a radio transceiver for up converting, in two stages, a base band information signal to an RF information signal wherein a first said stage converts said base band information signal to an IF information signal and a second said stage converts said IF information signal to said RF information signal, said method comprising:
-
(a) up converting said base band information signal to said IF information signal using image rejection up conversion means configured for achieving substantial image signal rejection and an IF oscillator signal;
(b) up converting said IF information signal to said RF information signal using an RF oscillator signal; and
,(c) generating each of said RF and IF oscillator signals whereby said IF oscillator signal is an integer (N) sub-harmonic of said RF oscillator signal, including preselecting the frequency value of said IF oscillator signal to be within the operating frequency band of said image rejection up conversion means. - View Dependent Claims (19, 20)
-
Specification