초록 ▼

A linear transmitter (101) using predistortion includes a modulator (103), a predistorter (107), a digital quadrature modulator (111), an upconverter (113), a power amplifier (115), and an antenna (117). In addition, the transmitter (101) has a feedback loop including a coupler (119), a downconverte

A linear transmitter (101) using predistortion includes a modulator (103), a predistorter (107), a digital quadrature modulator (111), an upconverter (113), a power amplifier (115), and an antenna (117). In addition, the transmitter (101) has a feedback loop including a coupler (119), a downconverter (123), a digital quadrature demodulator (125), and a trainer (131). The digital data to be transmitted is provided into the modulator (103), which converts the digital data into in-phase and quadrature component signals. The in-phase and quadrature component signals are then provided to the predistorter (107), which "predistorts" the component signals prior to amplification. The digital quadrature modulator (111) converts the component signals into a single analog signal. The upconverter (113) upconverts this signal from the predistorter (107) into the desired frequency of transmission, which is provided to the power amplifier (115) and the antenna (117) for amplification and broadcast. The coupler (119) provides a portion of the amplified signal to the analog downconverter (123), which lowers the frequency of this signal to a range that is easily processed. The signal is then provided to the digital quadrature demodulator (125), which outputs the in-phase and quadrature component signals of the signal. These in-phase and quadrature component signals are provided to the trainer (131) which analyzes them with the output signals from the modulator. The trainer (131) compares these signals and updates the predistorter (107) so that the digital quadrature demodulator (125) output signals are substantially equivalent to the modulator (103) output signals.

대표청구항 ▼

[ The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:] [1.] A transmitter for substantially linearly transmitting signals at a broadcast frequency, the transmitter comprising:a digital modulator coupled to receive digital data, wherein said

[ The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:] [1.] A transmitter for substantially linearly transmitting signals at a broadcast frequency, the transmitter comprising:a digital modulator coupled to receive digital data, wherein said modulator is capable of providing an in-phase signal and a quadrature signal dependent on said digital data;a predistorter coupled to said digital modulator, wherein said predistorter is capable of providing a predistorted in-phase signal dependent on said in-phase signal provided by said digital modulator and a predistorted quadrature signal dependent on said quadrature signal provided by said digital modulator;a digital quadrature modulator coupled to said predistorter, wherein said digital quadrature modulator is capable of providing a digital predistorted signal dependent on a combination of said predistorted in-phase signal and said predistorted quadrature signal provided by said predistorter;a digital-to-analog converter coupled to said digital quadrature modulator, wherein said digital-to-analog converter is capable of providing an analog predistorted signal dependent on said digital predistorted signal provided by said digital quadrature modulator;a power amplifier coupled to said digital-to-analog converter, wherein said power amplifier is capable of providing an amplified analog signal dependent on analog predistorted signal provided by said digital-to-analog converter;an antenna coupled to said power amplifier, wherein said antenna is capable of broadcasting said amplified analog signal provided by said power amplifier;a coupler coupled to said power amplifier, wherein said coupler is capable of providing a receive signal dependent on said amplified analog signal provided by said power amplifier;an analog-to-digital converter coupled to said coupler, wherein said analog-to-digital converter is capable of providing a digital receive signal dependent on said receive signal provided by said coupler;a digital quadrature demodulator coupled to said analog-to-digital converter, wherein said digital quadrature demodulator is capable of providing a feedback in-phase signal and a feedback quadrature signal dependent on said digital receive signal provided by said analog-to-digital converter;a trainer coupled to said digital quadrature demodulator, said predistorter and said digital modulator, wherein said trainer is capable of providing a trainer signal to said predistorter, said trainer signal being dependent on said feedback in-phase signal, said feedback quadrature signal, said in-phase signal, and said quadrature signal, wherein a subsequent predistorted in-phase signal and a subsequent predistorted quadrature signal provided by said predistorter are dependent on said trainer signal and subsequent in-phase and quadrature signals provided by said digital modulator; anda controller coupled to said digital modulator, said predistorter, and said trainer, wherein said digital modulator, said predistorter, and said trainer are reconfigurable, said controller being capable of selectably providing reconfiguration signals to said digital modulator, said predistorter, and said trainer, whereby said digital modulator, said predistorter, and said trainer are selectably reconfigured.