Automatic power level control circuit for a transceiver device
First Claim
1. A radio frequency transmitter comprising:
- a low-frequency stage including a digital to analog converter having an input for receiving an adjustable control voltage;
a radio frequency output stage; and
a power level control circuit including;
a detector circuit having a detector input and a detector output, the detector input being connected to said radio frequency output stage;
a comparator circuit having a comparator input and a comparator output, said comparator input being configured to receive an output signal from said detector output and a reference signal, wherein said comparator output is connected to said digital analog converter to provide the adjustable control voltage on the basis of the detector output signal and the reference signal.
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Accused Products
Abstract
An automatic power level control circuit provides output power control of a transmitter device as used in wireless LAN applications in that an output signal is detected and a corresponding control voltage of a DAC in the base band section is corresponding adjusted. Preferably, the measurement of the output power is carried out during a first transmit cycle and the DAC is adjusted after completion of the first transmit cycle and prior to the begin of a subsequent transmit cycle. Thus, a reliable output level control is obtained with a minimum number of radio frequency components, wherein the control loop shows an enhanced stability due to the time-discrete control operation.
18 Citations
25 Claims
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1. A radio frequency transmitter comprising:
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a low-frequency stage including a digital to analog converter having an input for receiving an adjustable control voltage;
a radio frequency output stage; and
a power level control circuit including;
a detector circuit having a detector input and a detector output, the detector input being connected to said radio frequency output stage;
a comparator circuit having a comparator input and a comparator output, said comparator input being configured to receive an output signal from said detector output and a reference signal, wherein said comparator output is connected to said digital analog converter to provide the adjustable control voltage on the basis of the detector output signal and the reference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of controlling an output power level of a radio frequency transmitter, the method comprising;
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detecting the output power level during a first transmit cycle to obtain a detection signal;
comparing said detection signal of said first transmit cycle with a predefined reference signal to generate a control signal; and
controlling the output power level of a second transmit cycle on the basis of said control signal. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method of controlling an RF output power level of a direct-conversion transceiver device for WLAN application, the method comprising:
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detecting the output power level;
establishing a control signal on the basis of said detection; and
controlling a base band signal on the basis of said control signal to adjust said output power level. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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Specification