SINGLE AMPLIFIER FILTER FOR CONSTANT GROUP DELAY IN RADIO FREQUENCY TRANSMITTERS

摘要

Apparatus and systems are provided for a single amplifier filter capable of a high quality factor. A filter comprises an amplifier having an amplifier input and an amplifier output, wherein the amplifier is configured to produce an output signal at the amplifier output based on a signal at the amplifier input. A first resistive element is coupled between an input node and the amplifier input, a second resistive element is coupled between a first node and the amplifier input, and a third resistive element is coupled between the amplifier output and the first node. A first capacitive element is coupled between the amplifier output and the amplifier input. The filter comprises a second node for an inverse of the output signal, wherein a second capacitive element is coupled between the first node and the second node.

主权项

1. A radio frequency transmitter comprising:
a digital-to-analog conversion module configured to generate an input signal based on a baseband signal; a first filter having a cutoff frequency, wherein the first filter is configured to generate a first signal by attenuating frequency components of a second signal above the cutoff frequency; a second filter coupled between the first filter and the digital-to-analog conversion module, the second filter having only one amplifier, wherein the second filter is configured to generate the second signal based on the input signal by compensating for a phase response of the first filter such that a group delay of the first signal relative to the input signal is substantially constant for frequencies less than the cutoff frequency; and a modulation module coupled to the first filter, the modulation module being configured to generate an output signal by modulating the first signal using a carrier signal.