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US 5,101,175 AGranted
Power control method for a voltage controlled power amplifier and circuitry used in the method
AssigneeNokia Mobile Phones Ltd.
InventorRisto Vaisanen
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AssigneeNokia Mobile Phones Ltd.
InventorRisto Vaisanen
Estimating the term…
In a digital radio telephone transmitter an output pulse with e.g. cos.sup.2 -shaped edges is produced by a voltage controlled power amplifier (4). When known control loop circuitry is used, the power (Pout) of the output pulse will rise almost step-wise at the beginning of the pulse, which leads to the spreading of the spectrum and to rise time delays of the output pulse with respect to the control pulse (TXC) at different power levels. According to the invention a good cos.sup.2 -shape of the output pulse (Pout) and its tracking of the control pulse (TXC) almost without delay is achieved so that a squarewave pulse (V.sub.p) is added to the control voltage (V2) of the power amplifier (4), the pulse (V.sub.p) starting and ending substantially at the same time as the control pulse (TXC). In a preferred embodiment the squarewave pulse (V.sub.p) is added to the control voltage (V2) only during that time when the control voltage (V2) is below that value, at which the control loop begins to operate.
A method for controlling the rising and falling edges of an output pulse of a voltage controlled power amplifier (4) to track a waveform of a control pulse (TXC) when the power amplifier is controlled with a control loop producing a control voltage (V2) with the aid of a voltage (V1) proportional to the output pulse power (Pout) and with the aid of a control pulse (TXC), whose rising and falling edges are e.g. cos.sup.2 -shaped, wherein a square wave pulse (Vp) is added to the control voltage (V2) of the power amplifier, the pulse (Vp) starting and ending substantially at the same times as the control pulse (TXC).
Circuitry to control the rising and falling edges of an output pulse of a voltage controlled power amplifier (4) to track a waveform of a control pulse (TXC) when the power amplifier is controlled with a control loop producing a control voltage (V2) with the aid of a voltage (V1) proportional to the output pulse power (Pout) and with the aid of a control pulse (TXC), whose rising and falling edges are e.g. cos.sup.2 -shaped, comprising a summing circuit, in which a squarewave pulse (Vp) is added to the control voltage (V2) of the power amplifier, the pulse (Vp) starting and ending substantially at the same time as the control pulse (TXC).
A method for controlling the rising and falling edges of an output pulse signal of a voltage controlled power amplifier to track a selected waveform, said power amplifier beginning to output power when a predetermined level of control voltage signal is applied thereto, comprising the steps:
A circuit to control the rising and falling edges of an output pulse signal of a voltage controlled power amplifier to a preselected waveform, said power amplifier beginning to output power when a predetermined level of control voltage signal is applied thereto, comprising:
Dependencies are inferred from the claim text.