RF variable gain tuned output amplifier which maintains high Q in saturation
First Claim
1. An amplifier for amplifying to an output RF signals applied to an input, CHARACTERIZED BY:
- a differential pair of transistors having a common output and two outputs and two inputs, the inputs coupling to the input of the amplifier and the two outputs coupling to the output of the amplifier;
a current source coupling to the common output of the transistors;
a resonant circuit connected between the two outputs of the transistors; and
high impedance means having a high impedance to RF signals connected between the two outputs of the transistors and a power supply terminal to provide a path for current to the transistors;
wherein RF signals on the two outputs of the differential pair of transistors are not bypassed to ground.
1 Assignment
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Accused Products
Abstract
An amplifier with variable gain which maintains high Q when saturated. A resonant circuit is connected between collector outputs of a differential pair of transistors and RF chokes couple DC supply current to the transistors. The chokes have a high impedance at the desired frequency. The emitters of the differential pair of transistors couple together to form a common output which is connected to a current source. The amount of current from the current source substantially controls the gain of the amplifier. Because the resonant circuit is not shunted with a low impedance even when one of the transistors saturates, the Q of the resonant circuit is maintained.
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Citations
6 Claims
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1. An amplifier for amplifying to an output RF signals applied to an input, CHARACTERIZED BY:
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a differential pair of transistors having a common output and two outputs and two inputs, the inputs coupling to the input of the amplifier and the two outputs coupling to the output of the amplifier; a current source coupling to the common output of the transistors; a resonant circuit connected between the two outputs of the transistors; and high impedance means having a high impedance to RF signals connected between the two outputs of the transistors and a power supply terminal to provide a path for current to the transistors; wherein RF signals on the two outputs of the differential pair of transistors are not bypassed to ground. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification