Mobile station having dual band RF detector and gain control

Claim 2

A dual band RF transmitter as in claim 1, and further comprising an error amplifier having a first input coupled to an output of said RF detector, a second input coupled to a transmitter power setting control signal, and an output providing an error signal having a magnitude that is a function of a difference between a magnitude of said output of said RF detector and said transmitter power control setting signal, said error signal being coupled to both of said first and second RF amplifier sections for controlling the gain of an active one of said first and second RF amplifier sections.

Claim 3

A dual band RF transmitter as in claim 1 or 2, wherein said first and second RF amplifier sections each have an input coupled to an control signal and are responsive to said control signal for enabling only one of said first and second RF amplifier sections for operation at any given time.

Claim 4

A dual band RF transmitter as in any preceding claim, wherein said directional coupler is comprised of a plurality of tuned strip lines, a first strip line having an input coupled to said output of said first RF amplifier section, a second strip line having an input coupled to said output of said second RF amplifier section, and a third strip line that is disposed relative to said first and second strip lines for having an RF signal induced therein from one of said first and second strip lines for providing said RF output signal having a magnitude that is a function of the power of the amplified RF signal passing through one of said first and second RF strip lines.

Claim 5

A dual band RF transmitter as in claim 4, wherein said first strip line has an impedance of about 50 ohms, wherein said second strip line has an impedance of about 50 ohms, and wherein said third strip line has an impedance of about 100 ohms.

Claim 6

A dual band RF transmitter as in claim 1, wherein said impedance matching circuit includes an impedance matching network, an input node of said impedance matching circuit being coupled to said impedance matching network, said impedance matching network being comprised of a plurality of strip lines, a first strip line having a first end coupled to the input node and a second end, a second strip line having a first end coupled to ground and a second end coupled to the second end of the first strip line at a common node, and a third strip line having a first end coupled to the common node and a second end coupled to said RF detector.

Claim 7

A dual band RF transmitter as in claim 4 or 6, wherein the first band of frequencies includes 836 MHz, wherein the second band of frequencies includes 1880 MHz, wherein said third strip line has a length equal to about 12.4 mm and a width equal to about 0.2 mm, said second strip line has a length equal to about 14.3 mm and a width equal to about 0.2 mm, and said first strip line has a length equal to about 2.2 mm and a width equal to about 0.2 mm.

Claim 8

A dual band RF transmitter as in claim 7, wherein said impedance matching network is further comprised of a capacitance having a first terminal coupled to said common node and a second terminal coupled to ground.

Claim 9

A dual band RF transmitter as in claim 8, wherein said impedance matching network is further comprised of a capacitance having a first terminal coupled to said common node and a second terminal coupled to ground, said capacitance having a value of about 1.8 pF.

Claim 10

A dual band mobile station, comprising: at least one antenna; a transceiver coupled to said at least one antenna; and a controller coupled to said transceiver for controlling an operation of said transceiver when operating in one of a first band of frequencies and a second band of frequencies; wherein said transceiver is comprised of a dual band transmitter comprised of first and second variable gain RF amplifier sections each having an output coupled to said at least one antenna through a directional coupler, said directional coupler having an output providing an RF output signal having a magnitude that is a function of the power of an amplified RF signal passing through said directional coupler from a selected one of said first and second RF amplifier sections, one of said first and second RF sections being selected for operation in accordance with a mode signal generated by said controller; an RF detector having an output for providing an RF power detection signal; an impedance matching circuit interposed between said output of said directional coupler and an input of said RF detector, said impedance matching circuit operating so as to cause said RF power detection signal to have about the same magnitude for a given level of output power from either of said first and second RF amplifier sections; and an error amplifier having a first input coupled to an output of said RF detector, a second input coupled to a transmitter power control setting signal generated by said controller, and an output providing an error signal having a magnitude that is a function of a difference between a magnitude of said output of said RF detector and said transmitter power control setting signal, said error signal being coupled to both of said first and second RF amplifier sections for controlling the gain of the selected one of said first and second RF amplifier sections.

Claim 11

A dual band mobile station as in claim 10, wherein a non-selected one of said first and second RF amplifier sections is placed in a low power consumption mode.

Claim 12

A dual band RF transmitter, comprising: a first variable gain RF amplifier section having an output that provides, when enabled by a mode control signal, an amplified RF signal for frequencies within a first band of frequencies; a second variable gain RF amplifier section having an output that provides, when enabled by said mode control signal, an amplified RF signal for frequencies within a second band of frequencies; a first directional coupler having an input coupled to said output of said first RF amplifier section and an output providing a first RF output signal having a magnitude that is a function of the power of an amplified RF signal passing through said first directional coupler from said first RF amplifier section; a second directional coupler having an input coupled to said output of said second RF amplifier section and an output providing a second RF output signal having a magnitude that is a function of the power of an amplified RF signal passing through said second directional coupler from said second RF amplifier section; a first RF detector having an input coupled to said first RF output signal for providing a first RF power detection signal; a second RF detector having an input coupled to said second RF output signal for providing a second RF power detection signal; and an error amplifier having a first input coupled to both of said first and second RF power detection signals, a second input coupled to a transmitter power control setting signal, and an output providing an error signal having a magnitude that is a function of a difference between a magnitude of an active one of said RF power detection signals and said transmitter power control setting signal, said error signal being coupled to both of said first and second RF amplifier sections for controlling the gain of the active one of said first and second RF amplifier sections.

Claim 14

A method as set forth in claim 13, wherein the step of selectively enabling includes a step of placing a non-enabled RF amplifier section into a low power consumption mode.

Claim 15

A method as set forth in claim 13 or 14, wherein the step of detecting includes the steps of: outputting a detection signal from a directional coupler through which the amplified RF signal from each RF amplifier section passes, when enabled, the directional coupler having a characteristic output impedance; inputting the detection signal to an RF detector; and providing an impedance matching circuit between the directional coupler and the RF detector.

Claim 16

A multi-band mobile station, comprising: a plurality of RF amplifier sections, one for each frequency band; a controller for selectively enabling, when transmitting, only one of the RF amplifier sections; a circuit for detecting the power of an amplified RF signal that is output from the enabled one of the RF amplifier sections; and a single error detection circuit, coupled to said detecting circuit, for generating an error signal, the error signal having a magnitude that is indicative of a difference between the detected power and a desired power, the error signal being coupled to the enabled one of the RF amplifier sections so as to minimize the magnitude of the error signal.

Claim 17

A multi-mode mobile station as in claim 16, wherein the controller places a non-enabled RF amplifier section into a low power consumption mode.

Claim 18

A multi-mode mobile station as in claim 16 or 17, wherein said detecting circuit is comprised of: a directional coupler for outputting a detection signal in response to a presence of an amplified RF signal from an enabled RF amplifier section, the directional coupler having a characteristic output impedance; an RF detector coupled to said detection signal; and an impedance matching circuit coupled between said directional coupler and said RF detector.

Claim 19

An invention as in claim 10, 13, or 16, wherein one frequency band includes 836 MHz, and wherein another frequency band includes 1880 MHz.

Claim 20

A dual band transceiver comprising first and second RF amplifier sections for respective frequency bands, a directional coupler circuit for detecting the power of an amplified RF signal that is output from the enabled one of the RF amplifier sections, and an error detection circuit, coupled to the detecting circuit, for generating an error signal that has a magnitude that is indicative of a difference between the detected power of the enabled RF amplifier section and a desired power, the gain of the respectively enabled one of the RF amplifier sections being responsive to the error signal such that the magnitude of the error signal is reduced.

Claim 21

The directional coupler circuit includes an RF detector coupled to the directional coupler, and an impedance matching circuit coupled between the directional coupler and the RF detector such that the impedance matching circuit operates to cause the signal output from the RF detector to have about the same magnitude for a given level of output power from any one of the enabled RF amplifier sections.