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US 6,272,330 B1Granted
Radio receiver and gain controlled amplifier therefor
AssigneeU.S. Philips Corporation
InventorJohn D. Speake
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AssigneeU.S. Philips Corporation
InventorJohn D. Speake
Estimating the term…
A gain controlled radio receiver for a selective call system, includes a multi-step gain controlled RF amplifier (44) coupled to receive an input signal and a measuring circuit (42) for measuring the level of a wanted frequency down converted signal. The multi-step gain controlled amplifier (44) has an input terminal (RIP, RIN), N gain stages (76A to 76E), where N is an integer of at least 2, having outputs coupled to a common output stage (82). A first of the N gain stages (76A) is coupled to the input terminal (RIP, RIN), and an (N−1) stage capacitive ladder attenuator (86) has an input coupled to the input terminal and outputs coupled respectively to an input of each of the second to Nth gain stages (76B to 76E). The measuring circuit (42) has a level control output (45) for switching-on a selected one of the gain stages which provides an amplified signal to the common output stage for frequency down conversion and demodulation.
A receiver comprising means for receiving an input signal, a multi-step gain controlled RF amplifier coupled to said receiving means, means for frequency down-converting the amplified signal, means for measuring the level of a wanted signal, and means for demodulating said signal, wherein the multi-step gain controlled RF amplifier comprises an input terminal, an N−1 stage ladder attenuator having an input coupled to the input terminal and having N−1 successive outputs, where N is an integer of at least 2, each stage of said ladder attenuator having an attenuation step to produce progressively increased attenuation between the input terminal and each successive one of the N−1 outputs, N gain stages having outputs coupled to a common output, a first of the gain stages having an input coupled to said input terminal and the second to Nth of the gain stages having an input coupled to a different one of the N−1 outputs of the ladder attenuator, and said measuring means has a level control output for switching-on a selected one of the gain stages.
A gain controlled amplifier comprising an input terminal, an N−1 stage ladder attenuator having an input coupled to the input terminal and having N−1 successive outputs, where N is an integer of at least 2, each stage of said ladder attenuator having an attenuation step to produce progressively increased attenuation between the input terminal and each successive one of the N−1 outputs, N gain stages having outputs coupled to a common output, a first of the gain stages having an input coupled to said input terminal and the second to Nth of the gain stages having an input coupled to a different one of the N−1 outputs of the ladder attenuator, and switching means responsive to an external signal for switching-on a selected one of the gain stages.
A gain controlled amplifier comprising an input terminal, an N−1 stage ladder attenuator having an input coupled to the input terminal and having N−1 successive outputs, where N is an integer of at least 2, each stage of said ladder attenuator having an attenuation step to produce progressively increased attenuation between the input terminal and each successive one of the N−1 outputs, and N selectively activatable gain stages having outputs coupled to feed to a common output, a first of the gain stages having an input coupled to said input terminal and the second to Nth of the gain stages having an input coupled to a different one of the N−1 outputs of the ladder attenuator.
Dependencies are inferred from the claim text.