Abstract: A wireless subscriber communication unit (200) comprises an antenna arrangement (202, 330, 430) for radiating and/or receiving electromagnetic signals. A transmitter (220) and/or a receiver (210) is/are operably coupled to the antenna arrangement (202, 330, 430), for transmitting/receiving a radio signal. An antenna arrangement comprises an internal antenna located within the wireless communication unit (200) and an external antenna located substantially outside of the wireless communication unit, such that both the internal antenna (330, 430) and the external antenna (202) co-operate on substantially the same electromagnetic signal. In this manner, by provision of both an internal and an external antenna the wireless subscriber communication unit is able to function adequately should an antenna become disconnected, malfunction, or its performance suffer from impedance mismatching.

Abstract: A wireless communication unit (300) comprises a linearized transmitter (325, 500) having a power amplifier (324), a forward path and a feedback path for feeding back a portion of a signal to be transmitted, wherein the feedback path and forward path form two loops in quadrature. A processor (322) applies one or more training signals to a first quadrature circuit loop and a second quadrature circuit loop and measures a quadrature imbalance between the first and second quadrature circuit loops. In response the processor adjusts at least one parameter setting of a loop adjustment function (442) to balance the quadrature circuit loops. A linearized transmitter integrated circuit and method of training are also described. The measuring and compensating for any loop imbalance between digital ‘I’ and ‘Q’ paths around a feedback path provides improved accuracy and stability in phase and/or amplitude.

Abstract: A multi-frequency band antenna (100) includes a dual-pitch coil (120, 130), and a top insert (140), operably coupled to an antenna base (105). The multi-frequency band antenna (100) is configured to radiate electromagnetic signals at a lower frequency 230) of multi-frequencies using substantially the whole of the dual-pitch coil (120, 130); and at a higher frequency (240) of said multi-frequencies using a length of said antenna base (105, 110) and a portion of said dual-pitch coil (120). A first portion of the dual-pitch coil has a longer pitch than a second portion of the coil and the first portion has a first end attached to the antenna base and a second end attached to the second portion, and the second portion has an effective electrical length substantially equal to a wavelength (?) of radiation having a frequency corresponding to a frequency in the second band.

Abstract: An automatic gain control (AGC) method and circuit (10) within a receiver uses a digital state machine (26) to implement the AGC function. independent from interaction with a host processor (36) and for multiple modulation protocols without duplicating circuitry. Modulation protocol and parameters for any of various gain responses are stored in a register (29). Multiple states, each corresponding to a predetermined range of RF input signal strength, are stored in the register. Each state contains parameters that determine a gain control signal for controlling a variable gain amplifier (16). The states are independent and may be selectively disabled to create asymmetric responses. Within any state, an adaptable number of iterations may be set to implement a different update rate or step size after a predetermined number of closed loop gain change iterations has not resulted in a transition to a state that represents a desired output gain.

Abstract: An automatic gain control (AGC) circuit including: a forward transmission path (214) having applied at its input an input RF signal and to provide at its output an output signal; a variable gain AGC amplifier (210) in the forward transmission path for processing the input RF signal, which amplifier has a control input 240 and is responsive to a control signal applied at its control input to vary its gain; a feedback loop (220 to 240), coupled from the output of the forward transmission path and to the control input of the AGC amplifier; an integrator (230, 232), coupled to the control input of the amplifier; a voltage source (234), coupled to the integrator and to the control input of the amplifiers; and a further variable gain device (215) for varying the gain or attenuation of a signal applied to the control input of the AGC amplifier.

Abstract: A voltage controlled oscillator (VCO) for connection and operation in a phase locked loop arrangement has two or more operational states in each of which the VCO circuit is operable to provide activation of a selected one of two or more different phase locked loops when connected to the VCO circuit, the VCO circuit including switching means for switching the state of the VCO circuit to allow the operational state of the VCO to be selected. A frequency synthesizer circuit for use in radio communications to generate a stable frequency signal, the circuit includes the VCO circuit. The synthesizer circuit includes two or more different phase locked loops each having a first state in which the loop is activated and a second state in which the loop is deactivated. At least part of the VCO circuit is connected in and shared by the loops, so that the loop to be activated can be selected by selecting the operational state of the VCO.

Abstract: A device for linear transmitter 150 with improved loop gain stabilization. The linear transmitter 150 includes a main amplifier loop 178 and an auxiliary loop 176. The device includes an adjustable driver 159, connected within the main amplifier feedback loop 178 and further connected to the auxiliary loop 176. The adjustable driver 159 receives an input signal from main amplifier feedback loop 178, amplifies it in accordance with a gain control signal received from the auxiliary loop 176 and provides the amplified signal to main amplifier feedback loop 178.

Abstract: A voltage controlled oscillator (VCO) for connection and operation in a phase locked loop arrangement has two or more operational states in each of which the VCO circuit is operable to provide activation of a selected one of two or more different phase locked loops when connected to the VCO circuit, the VCO circuit including switching means for switching the state of the VCO circuit to allow the operational state of the VCO to be selected.

Abstract: A radio is described having a synthesizer (17) and a VCO (18). Each of the synthesizer and the VCO has a connection to a ground plane (13) of the radio. The ground plane connection of the VCO has a first capacitor (43) and a further ground connection (40) is provided between the VCO and the synthesizer for providing a common baseband ground for the VCO and the synthesizer, isolated with respect to baseband frequency currents in the ground plane of the radio. The arrangement addresses problems arising in radios having power amplifiers with severe output amplifier variations, such as are found in linear radios.

Abstract: A method of calibration of a power amplifier for a radio transmitter is described (FIG. 6), which is particularly relevant to the field of training of linear power amplifiers. In a calibration mode, an increasing signal, e.g. a ramp signal (153), is provided to the amplifier until the amplifier commences clipping (155). A value for said input is identified (155) which does not cause clipping. Thereafter, in operational mode, the increasing input signal is limited to that level. In this manner, interference during training is avoided. A radio transmitter is also provided.

Abstract: This invention relates to a radio transmitter having a power amplifier and a linearizer arrangement, for example Cartesian feedback, for compensating for non-linearity in the power amplifier. A training signal is applied to the amplifier (36) and the linearizer arrangement is adjusted during a training mode of operation. In one embodiment, a look-up table (23) is provided for storing predetermined operating condition adjustment parameters. According to an operating condition input (e.g. frequency, temperature) control means (21) select operating condition adjustment parameters during the training mode and adjust the training signal to compensate for loop gain variations during the training mode. Automatic gain control (26) may be provided in the amplifier loop for activation during at least a portion of the training mode of operation to maintain constant closed loop gain.