Patent ID: 6469582
Filing Date: 2002-10-22
Classification: H03H,H04B

Abstract:
A monolithic radio frequency circuit comprising:an RF input; a mixer having a first input; a local oscillator having an output coupled to a second input to the mixer; and a baseband signal processor having an input coupled to an output of the mixer and having an output coupled to a user interface; and a RF amplifier including an input coupled to the RE input, an output coupled to the first input of the mixer, and a voltage-tunable frequency selection component, the RF amplifier comprising: first amplifier means having a first input and a first output, a first input impedance associated with the first input being much less than a first output impedance associated with the first output, the first amplifier means having a voltage gain of slightly less than one, the first output coupled to the input of the RF amplifier; second amplifier means having a second input and a second output, a second input impedance associated with the second input being much larger than a second output impedance associated with the second output, the second amplifier means having a voltage gain of greater than one, the second input being coupled to the first output to form a filter input; first phase shifting means coupled to the output of the second amplifier means and the input of the first amplifier means; and second phase shifting means coupled to the filter input, the first phase shifting means, the second phase shifting means, the first amplifier means and the second amplifier means for collectively providing a frequency dependent impedance at the filter input.