Abstract:
The present invention discloses a proactive gain control system (200) for a communications receiver. The proactive gain control system (200) includes a variable gain module (220) for outputting an output signal in response to an input signal. A detector (204) detects the output signal and outputs a detection signal representing a signal strength of the output signal. A traffic monitor (206) monitors the output signal and outputs a traffic profile signal indicating that a traffic profile for the input signal will change. A gain computing module (208) outputs a gain adjustment value in response to the detection signal and the traffic profile signal. A gain control module (210) outputs a gain control signal to the variable gain module (220), which determines a gain between the input and output signals, in response to the gain adjustment value.
Abstract:
The invention enables a compromise between DC offset rejection and image rejection through the use of a bandpass filter having a variable center frequency.
Abstract:
PROBLEM TO BE SOLVED: To reduce distortion, improve reception sensitivity, and save power by taking into consideration two conditions of reception strength and C/N at demodulation. SOLUTION: A first low noise amplifier 22 and a first reception processing section 27 are connected by a first cable 26, a bypass circuit 23 for bypassing the first low noise amplifier 22 is connected in parallel with the first low noise amplifier 22, when the strength of a terrestrial digital broadcast signal is a prescribed value E or over and the C/N is a first prescribed value C1 or over and a second prescribed value C2 or below, which is higher than the first prescribed value C1, the terrestrial digital broadcast signal is fed to the first cable 26 via the first low noise amplifier 22, and when the C/N is the first prescribed value C1 or below or the second prescribed value C2 or over, the terrestrial digital broadcast signal is not given to the first low noise amplifier 22, passes through the bypass circuit 23 and is fed to the first cable 26. COPYRIGHT: (C)2007,JPO&INPIT
Abstract:
An apparatus for realizing automatic gain control in OFDMA system is provided, the apparatus includes: the automatic gain controller, the Analog-Digital Converter and baseband processing module. A method for realizing automatic gain control in OFDMA system is provided, the method uses the following steps: measuring the Carrier to Interference-plus-Noise Ratio and the receiving power on the data burst of each uplink on a frame-by-frame basis; computing the Interference-plus-Noise power of the (n-1)th frame; obtaining the Interference-plus-Noise receiving power and the available signal receiving power of the nth frame; computing the total receiving power of the nth frame; and obtaining the needed digital AGC gain value according to the corresponding relationship between the total receiving power and the AGC gain value of the nth frame. Using the apparatus and method for realizing automatic gain control in OFDMA system, estimating the available receiving power of the current frame with the amounts of the power adjustment from the base station, the total receiving power of the current frame may be more accurately computed, and the automatic gain control can be realized through the corresponding relationship between the total receiving power and the digital AGC gain.
Abstract:
A method and apparatus for limiting the effect of interfering transmission on a Global Positioning System (GPS) receiver is disclosed. A first mode of operation of the GPS receiver is provided wherein the AGC of the receiver is operated in a linear state. A second mode of operation of the GPS receiver is provided wherein the AGC of the receiver is operated in a non-linear state. A first signal is provided indicating a presence of a jamming signal. In response to the first signal the GPS receiver is switched from the first mode of operation to the second mode of operation.
Abstract:
A receiver for processing a signal comprises a first amplifier circuit and a second amplifier circuit. The first amplifier circuit is operated in association with a first gain profile. The second amplifier circuit is operated in association with a second gain profile. The receiver further comprises a gain control circuit that determines a quality indicator associated with a modulated signal. The gain control circuit adjusts the first gain profile and the second gain profile based at least in part upon the determined quality indicator.
Abstract:
A receiver for processing a signal comprises a first amplifier circuit and a second amplifier circuit. The first amplifier circuit is operated in association with a first gain profile. The second amplifier circuit is operated in association with a second gain profile. The receiver further comprises a gain control circuit that determines a quality indicator associated with a modulated signal. The gain control circuit adjusts the first gain profile and the second gain profile based at least in part upon the determined quality indicator.
Abstract:
In one aspect, an automatic gain control (AGC) for applying a variable gain to a broadband signal is provided. The AGC comprises a variable gain amplifier adapted to receive the broadband signal as an input, the variable gain amplifier configured to apply a variable gain to the broadband signal based on a value of a gain signal to provide an amplified broadband signal, and a controller to provide the gain signal to the variable gain amplifier, the controller adapted to determine the value of the gain signal based on at least one characteristic of the amplified broadband signal. In a further aspect, the one or more characteristic is a power characteristic of the broadband signal that facilitates control of the broadband signal within a desired power range.
Abstract:
The invention enables a gain adjustment in a receiver to improve signal quality by varying resistance of an input resistor array of a bandpass filter, the array having a plurality of resistors in series with switches that out of the path of the current when the resistors are in use.
Abstract:
Apparatus and methods for performing automatic gain control in a radar system. One embodiment of the system includes an attenuator that controls gain of signals received from a radar receiver. A digital signal processor determines coarse gain correction based on digitized noise data for a plurality of channels, determines fine gain correction based on the residual error after the coarse gain, and determines frequency vs. gain curve correction based on the digitized noise data for a plurality of channels and a mathematical model of frequency gain across a noise spectrum for the radar system. The result of the processor is a gain control signal that is sent to the attenuator to perform hardware gain control and a channel specific scale factor for software gain control. In one embodiment, the processor generates the gain control signal during an inactive scan mode of the radar system.