Nokia Telecommunications Oy

Nokia Networks Oy

Nokia Corporation

Allgon Ab

Chia-sam Wey

Kim Anh Tran

Jukka-Pekka Neitiniemi

Daniel Lee Iiams

A Power Amplifier (PA) exhibits non-linear characteristics as a result of Amplitude Modulation-Phase Modulation (AM-PM) conversions resulting in intermodulation. Inter-modulation affects the RF signal spectrum at the output of the PA. The invention presents a method and apparatus for reducing intermodulation generated at the output of a PA as a result of AM-PM conversion. Presented is a RF power detector utilized in feedback control circuitry where the induction of odd-order harmonics into the feedback path acts to reduce AM-PM intermodulation at the output of the PA. The RF power detector comprises an detector input for receiving RF power and a detector output containing a pre-corrected detected voltage. The RF power detector comprises a pre-correcting circuit for generating odd-order harmonics at a specific power level. The pre-correcting circuit induces odd-order harmonics into the detected portion of output power allowing feedback control circuit to compensate for AM conversions.-PM

Combined RF power detector and power precorrector

A method and apparatus for improving loop stability and speed of a power control loop. Adjacent channel interference in the ramp-up and ramp-down (transient) of a TDMA burst is reduced. The present invention is used in a burst when the transient response and loop speed are important in the design of the control loop. The loop bandwidth variation resulting from linear conversion power detector and PIN diode RF attenuators in the loop is reduced by reducing the upper end of the loop bandwidth and increasing the lower end of the loop bandwidth. The upper limit of the loop bandwidth determines the loop stability and the lower limit of the loop bandwidth determines the minimum speed of the loop. A reference signal is sampled and processed to set a gain of a feedback loop in the power control loop. The setting of the gain of the feedback loop using the reference signal increases the lower loop bandwidth to increase a loop speed and decreases the upper loop bandwidth to increase a loop stability for the power control loop. Accordingly, the present invention not only improves the loop stability, but also the speed of the loop.

Method and apparatus for improving loop stability and speed of a power control loop

A compensated RF power detector utilized in power control circuits for preventing power amplifier saturation. A power amplifier uses a power control circuit to maintain the power amplifier as efficiently and linearly as possible without distortion. The operating point of the power amplifier is defined as close to the 1 dB gain compression point as possible for maximum efficiency and linearity with minimum distortion. However, extreme temperature conditions affect the 1 dB gain compression point causing the power amplifier to operate too close to saturation resulting in distortion or spectral growth. In an embodiment, the compensated RF power detector comprises a RF power detector and a variable RC circuit. The RF power detector has a RF input for receiving RF power, a detector output for supplying a compensated detected voltage and, a detecting diode for generating a detected voltage in response to the received RF power. The detecting diode has an anode coupled to the RF input and a cathode coupled to the detector output. The variable RC circuit comprises a capacitor and a control circuit. The capacitor has a first lead coupled to the cathode of the detecting diode and a second lead coupled to the control circuit. The control circuit has a control output containing a varying resistance coupled to the second lead of the capacitor. The variations in the varying resistance result in the compensation of the detected voltage.

Compensated RF power detector

A temperature compensated variable attenuator comprising a variable attenuator having at least one diode with temperature variations across the at least one diode producing a temperature offset signal. A bias source coupled to the variable attenuator supplies a biasing signal to the at least one diode through a temperature compensation source. The temperature compensation source is coupled between the bias source and the variable attenuator with the temperature compensation source comprising at least one diode capable of producing a temperature offset signal approximately equivalent to the temperature offset signal produced by the first at least one diode. The approximate temperature offset signal subtracted from the biasing signal produces a temperature compensated bias signal that is supplied to the variable attenuator.

Temperature compensated variable attenuator

A precision-controlled logarithmic amplifier having reduced interference parameters. In an embodiment, the invention comprises a logarithmic amplifier having an output signal providing a logarithmic representation of an input signal. A precision-control circuit is coupled to the logarithmic amplifier. The precision-control circuit produces a bias and a saturation current that act to reduce the effects of bias and saturation currents that are produced in the logarithmic amplifier and affect the output signal of the logarithmic amplifier.

Precision-controlled logarithmic amplifier

A controlled detector circuit for generating a detector current to the input of a selected circuit. An unwanted operational voltage is generated on the input of the selected circuit affecting the precision of the detector circuit. The controlled detector circuit comprises a detector circuit having an RF input for detecting a RF signal and a detector output for providing the detector current. Operation of the detector circuit generates a voltage drop affecting the precision of the detector current. A control circuit having a control output connected to the detector output generates a control voltage for reducing the unwanted parameters affecting the precision of the detector current.

Precision controlled RF power detector circuit

A TM mode dielectric resonator and a filter comprising such a resonator. The resonator includes metallic walls defining a cavity. A dielectric resonator body is accommodated within the cavity. An end surface of the dielectric resonator body is located in the vicinity of one cavity wall, so as to provide a spacing between said end surface and said cavity wall, at least in a region corresponding to a portion of said end surface. The spacing can be obtained by washers, arranged between the dielectric resonator body and said cavity wall. It can also be obtained by means of a recess in said cavity wall, one or more protrusions on said cavity wall, or a metallic or dielectric ring arranged between the dielectric resonator body and said cavity wall.

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Arlington, TX, United States of America

Chia-sam Wey