Motorola Corporation

Freescale Semiconductor,inc.

Arul Balasubramaniyan

Dan William Nobbe

David S Peckham

Daniel Losser

A multiband and multimode transmitter circuit () includes two separate oscillators, such as at least a first oscillator circuit (), a second oscillator circuit (), a corresponding first signal processing circuit (), and second signal processing circuit () to produce a first output frequency signal () defined within the first or second band of frequencies in response to a transmitter input signal (). Each oscillator and corresponding signal processing circuit () may be optimized for the lowest power consumption while meeting the noise performance criteria in each of the multiple frequency bands. The multiband and multimode transmitter circuit () may produce the transmitter output signal () with either linear modulation or nonlinear modulation and at a first band or second band frequencies.

Multiband and multimode transmitter and method

The present invention describes a voltage controlled attenuator (VCA) to control an output power level of a radio frequency (RF) signal and to direct the RF signal to an appropriate path for a multi-mode and multi-band radiotelephone without using an external switch and without using multiple common VCAs. The present invention comprises a single differential amplifier and a plurality of steering blocks with each of steering blocks having a path dedicated to a specific RF band and a specific RF mode, having a pair of steering lines to control the RF signal level by having a differential voltage applied, and being capable of being disabled by having its steering lines grounded.

Voltage controlled attenuator for multi-band and multi-mode transmitter and method thereof

Systems and methods are described for a band switchable voltage controlled oscillator. A method comprises: operating said voltage controlled oscillator in a first frequency band by switching a first capacitive circuit having a capacitance that varies with a tuning voltage; and operating said voltage controlled oscillator in a second frequency band by switching a second capacitive circuit having a capacitance that does not vary with the tuning voltage. An apparatus comprises: a switchable variable capacitance circuit; a switchable fixed capacitance circuit coupled to the switchable variable capacitance circuit; a controller for selectively switching said switchable fixed and variable capacitance circuits; a fixed tank capacitance circuit coupled to the switchable fixed capacitance circuit; a main tuning voltage variable capacitance circuit coupled to the fixed tank capacitance circuit; a tank inductance coupled to the main tuning voltage variable capacitance circuit; and an amplifier circuit coupled to the tank inductance.

Band switchable voltage controlled oscillator with substantially constant tuning range

A variable gain element for adjusting a magnitude of an input signal. The variable gain element includes a first differential transistor pair having a first transistor coupled to a second transistor. A second differential transistor pair couples the second transistor to a supply voltage and to an output terminal of the first transistor. A load resistor couples the output terminal to the supply voltage. A control voltage applied to an input of the second differential pair causes a varying amount of current cancellation through the load resistor.

Voltage controlled variable gain element

A current-controlled FET resistor and a low supply, current-controlled FET Pi attenuator network are provided. The current-controlled FET resistor includes an FET having drain, source, and gate terminals, and a connection between the gate terminal and the drain terminal, wherein a resistance characteristic of the FET is proportional to an input current flowing into the drain terminal. The low supply, current-controlled FET Pi attenuator network includes a first current-controlled FET resistor connected between an input node and a ground node, a second current-controlled FET resistor connected between the input node and an output node, a third current-controlled FET resistor connected between the output node and the ground node, a DC return path connected in parallel between the output node and the ground node, a first DC blocking capacitor connected between a Pi attenuator network input and the input node, a second DC blocking capacitor connected between the input node and the first current-controlled FET resistor, and a third DC blocking capacitor connected between the output node and the third current-controlled FET resistor, wherein resistance characteristics of the current-controlled FET resistors vary in relation to input currents flowing into the drain terminals.

Low supply, current-controlled FET Pi attenuator

A dual FET differential voltage controlled attenuator includes a first voltage controlled FET transistor (M,), corresponding to a first control voltage terminal, and a second voltage controlled FET transistor (M,), corresponding to a second control voltage terminal. The first voltage controlled FET transistor attenuates a voltage at an attenuator output by regulating current through a first resistor (R,) connected between an attenuator output and a voltage supply node (Vcc), and the second voltage controlled FET transistor attenuates the voltage at the attenuator output by regulating current through a second resistor (R,) connected between the attenuator output and the voltage supply node. The first and second voltage controlled FET transistors attenuate the voltage at the attenuator output by generating differential currents in the first and second resistors, the differential currents giving a linear transfer function from an attenuator input to the attenuator output of the dual FET differential voltage controlled attenuator.

Growing community of inventors

Round Lake, IL, United States of America

Arul Balasubramaniyan