Abstract:
The disclosed apparatus and corresponding method uses amplifiers and a differential combiner to control the output power of a digital-to-analog upconverter and to isolate In-phase and Quadrature branches of the upconverter. First and second upconverters convert In-phase and Quadrature portions of a baseband digital value to respective first/second In-phase (l p /l n ) and first/second Quadrature (Q p /Q n ) analog components at RF. First and second amplifiers respectively amplify l p , l n and Q p , Q n to respectively generate amplified l p , l n and Q p , Q n signals. The first and second amplifiers each operate at a 50% duty cycle and in an interleaved fashion such that only one amplifier is active to generate an output at any time, and such that the amplified signals are output in an interleaved fashion. A differential combiner combines the amplified signals to generate the RF analog signal representative of the baseband digital value.
Abstract:
The wireless communication system includes a transmitter configured to transmit an input signal, and a receiver configured to receive an output signal from the transmitter and process the received signal to restore an original signal. The transmitter includes an IMpact Avalanche Transit Time (IMPATT) diode oscillator, a mixer, a filter and an amplifier. The IMPATT diode oscillator outputs an oscillation signal having a preset oscillation frequency. The mixer receives the input signal and the oscillation signal and performs frequency conversion. The filter eliminates noise from a frequency-converted signal output from the mixer. The amplifier amplifies the frequency-converted signal output from the filter and the oscillation signal output from the IMPATT diode oscillator, and transmits the amplified signals via an antenna.
Abstract:
An RF transceiver apparatus comprises transmitter circuitry arranged to convert signals from a baseband frequency to RF transmission frequencies and receiver circuitry arranged to convert signals from RF reception frequencies to the baseband frequency. The transmitter and receiver circuitry each comprise three mixers arranged to convert a signals between the baseband frequency, a first intermediate frequency; a second intermediate frequency that is higher than the transmission frequencies; and a second intermediate frequency to the transmission frequency.
Abstract:
The present invention relates generally to communications, and more specifically to a method and apparatus of modulating baseband and RF (radio frequency) signals. A modulator topology is disclosed in which an input signal x(t) is up-converted to an output signal y(t), either by mixing it with two mixing signals φ1 and φ2 ("pseudo-direct conversion" mode), or by mixing it with only one mixing signal φ2 ("direct-conversion" mode). In pseudo-direct modulation mode, the φ1 and φ2 mixing signals emulate a local oscillator signal; the product φ1* φ2 has significant power at the frequency of a local oscillator signal being emulated, but neither φ1 nor φ2 have significant power at the frequency of the input signal x(t), the LO signal being emulated, or the output signal φ1 φ2 x(t).
Abstract:
There is a need for an inexpensive, high-performance, fully-integrable, multi-standard transceiver, which suppresses spurious noise signals. The invention provides a topology that satisfies this need, using a first signal generator which produces an oscillator signal f1 and a second signal generator which produces a mono-tonal mixing signal φ2, where f1 is a multiple of the frequency of φ2; and a logic circuit for generating a multi-tonal mixing signal φ1, where φ1 * φ2 has significant power at the frequency of said local oscillator signal being emulated, neither of said cp1 nor said φ2 having significant power at the carrier frequency of said input signal x(t) or said LO signal being emulated.