Abstract: A radio frequency (RF) signal is received in a receiver, and various counts based on information from the signal can be obtained. Counts of a number of samples of the RF signal exceeding first and second thresholds can be accumulated during an accumulation window. From the first of these counts, it can be determined if the count exceeds a first metric corresponding to a first predetermined count value, and if so, a gain of an RF gain element can be reduced. From the second of these counts it can be determined if this count exceeds a second metric corresponding to a second predetermined count value, and if not, the gain can be increased.

Abstract: A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine.

Abstract: A multi-mode power amplifier includes a high-power mode amplifier circuit, a mid-power mode amplifier circuit, and a low power amplifier circuit, where the low-power mode amplifier circuit comprises a plurality of independently selectable power cell/amplifier branches. The multi-mode power amplifiers selectively enable or disable amplifier branches to provide multiple levels of amplification. Selectively enabling certain of a plurality of split collector amplifier branches provides multiple low power and ultra-low power amplifier modes without the impedance mismatch or board layout problems associated with an RF switch.

Abstract: Provided are a receiving apparatus and method for a wireless communication system using multiple antennas. A receiving method for a wireless communication system using multiple paths, the receiving method comprising: receiving signals through a predetermined number of multiple paths; sensing a carrier according to saturation state degrees of the signals, and providing saturation state information; calculating automatic gain components of the received signals by using the received signals and the saturation state information of the received signals; and performing a noise matching process to amplify noises on the predetermined multiple paths according to the automatic gain components during a predetermined period.

Abstract: A wireless communication receiver includes a multitude of look-up tables each storing a multitude of DC offset values associated with the gains of an amplification stage disposed in the wireless communication receiver. The entries for each look-up table are estimated during a stage of the calibration phase. During such a calibration stage, for each selected gain of an amplification stage, a search logic estimates a current DC offset number and compares it to a previous DC offset estimate that is fed back to the search logic. If the difference between the current and previous estimates is less than a predefined threshold value, the current estimate is treated as being associated with the DC offset of the selected gain of the amplification stage and is stored in the look-up table. This process is repeated for each selected gain of each amplification stage of interest until the look-up tables are populated.

Abstract: A method and apparatus for managing audio conflicts and priorities is disclosed. A mobile device (110) initiates a navigation application (410) and an audio application (415), each configured to utilize audio input and/or output components. The mobile device identifies (430, 435) a priority of a communication associated with the audio application and manages (440, 445) the audio input and output components based on the priority and other factors. In particular, the mobile device or components thereof can delay (440) an indication of the communication until a sufficient break in a route traversal is reached, can mute (445) the audio input component while the navigation application utilizes the audio output component, and/or can perform other functions related to the audio conflicts and priorities of the applications.

Abstract: The present invention discloses apparatus and method for fast and robust automatic gain control (AGC). By using the power statistics and/or the amplitude statistics of multiple pairs of signed ADC outputs, the additional gain control can be determined and included in a statistics-aided AGC to successfully complete the AGC function for a received signal having a dynamic range up to 100 dB within a few micro-seconds.

Abstract: There is provided a method for communications involving at least one text message. The method includes a sender apparatus transmitting at least one message, the at least one message including message data and at least one video filmlet; transmitting the message data over a first network and the at least one video filmlet to a server on a second network; and a recipient apparatus receiving the at least one message, the at least one message being combined and generated from the message data received from the first network and the at least one video filmlet received from the server. Advantageously, the at least one message may be generated in a manner as composed by a sender of the at least one message. It is preferable that the sender and recipient apparatus are able to support a data sync protocol on the second network.

Abstract: A zero bias power detector comprising a zero bias diode and an output boost circuit is provided. The output boost circuit comprises a zero bias transistor. The zero bias diode is not biased but outputs a rectifying signal according to a wireless signal. The zero bias transistor, not biased but coupled to the zero bias diode, is used for enhancing the rectifying signal.

Abstract: A technique for controlling operation of a communication subsystem is described. The subsystem is set to a first wake-up mode of operation, during which a state value from the system is read and stored in memory. The subsystem is then set to a sleep mode of operation after the first wake-up mode of operation, and to a second wake-up mode of operation after the sleep mode of operation. The stored state value is then read from the memory, where the subsystem is set to operate based on the read state value during a warm-up period of the second wake-up mode of operation.

Abstract: A radio frequency (RF) power amplifier (PA) is reconfigured to operate in a low power mode from a high power mode. The RF PA has a first RF amplifier is connected to the first and second inputs of a first transformation network. The RF PA has a second a second RF amplifier connected to a second transformation network. During high power mode, both RF amplifiers drive a load coupled to the transformation networks. In low power mode the first RF amplifier is disabled and the first and second inputs of the first transformation are coupled together so as to change the load impedance seen by the second RF amplifier. The second RF amplifier continues to supply power to the load during operation in the low power mode.

Abstract: A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine.

Abstract: Disclosed is a radio frequency (RF) receiver for receiving a communication channel modulated on one or more carrier frequencies. The receiver may include a gain adjustable RF amplifier, a wideband signal power measurement circuit, and control logic. The control logic may be adapted to use outputs of one or more measurement circuits to classify interfering signals based on measured signal power and spectral proximity to the one or more channel carrier frequencies, and to adjust the gain of the radio frequency amplifier based on the classification.

Abstract: A method for performing a call between a near-end user and a far-end user, which includes the following operations performed during the call by the near-end user's communications device. Automatic gain control (AGC) is performed to update a gain applied to an uplink speech signal. A frame is detected in a downlink signal that contains speech; in response, the updating of the gain is frozen. Other embodiments are also described and claimed.

Abstract: An active splitter circuit arrangement includes a first amplification module having a number of first input ports and first output ports. The first amplification module is configured to provide first stage amplification to a received input signal and produce from the amplified input signal a number of output signals, each substantially matching the input signal. Also included is a first gain control device configured to control a gain of the first amplification module. Next, a number of second amplification modules corresponding to the number of output signals has a number of second input ports respectively coupled to the first output ports. Each second amplification module is configured to receive a control signal from the second gain control device, provide second stage amplification to a corresponding one of the number of output signals based upon the control signal and produce an amplified output signal.

Abstract: An active splitter circuit arrangement includes a first amplification module having a number of first input ports and first output ports. The first amplification module is configured to provide first stage amplification to a received input signal and produce from the amplified input signal a number of output signals, each substantially matching the input signal. Also included is a first gain control device having a number of gain input ports respectively coupled to the first output ports and a gain output port coupled to at least one of the first input ports. The first gain control device is configured to control a gain of the first amplification module. Next, a number of second amplification modules corresponding to the number of output signals has a number of second input ports respectively coupled to the first output ports.

Abstract: A method for use in a digital communications receiver for controlling an input signal level (200) into an analog-to-digital converter (ADC) initially receives a sample sequence (201) where a threshold crossing rate is measured as a percentage samples of an input signal that exceed the threshold (203). The error between the measured threshold crossing rate and a desired reference threshold crossing rate is calculated (205) and an error signal is then utilized in a feedback loop to control the receiver gain such that the error is reduced (207).

Abstract: A communication device supporting multiple wireless protocols may share a common gain element in a coordinated manner. A first wireless protocol circuitry of the communication device may enter an active state, and in response to entering the active state, may determine whether a second wireless protocol circuitry of the communication device is active and whether the common gain element is currently shared. The gain element may be adjustable to amplify signals by an adjustable amount. The first wireless protocol circuitry may take control of the gain element from the second wireless protocol circuitry in response to determining that the second wireless protocol circuitry is active and the gain element is currently shared.

Abstract: A method of managing a Dedicated Short-Range Communication (DSRC) network in a vehicle having a primary DSRC system is provided. The method comprises detecting a secondary DSRC system operating in proximity to the vehicle and transmitting a suppression notice in response to detecting the secondary DSRC system, where the suppression notice conveys an instruction to the secondary DSRC system to suspend DSRC transmissions.

Abstract: A communication device reads and stores in memory a state value which was utilized for operating a communication subsystem during a wake-up period of the communication subsystem. The device then causes the communication subsystem to enter into a sleep mode. Subsequently, the device causes the communication subsystem to exit from the sleep mode and enter into a current wake-up period. The stored state value is provided to the communication subsystem for use in operating the communication subsystem during a warm-up period of the current wake-up period. After the warm-up period of the current wake up period, a current state value is provided from a state controller to the communication subsystem for use in operating the communication subsystem during the wake up period. The current state value is determined based on a detected signal level of a current signal received in the communication subsystem.

Abstract: An enhanced programmable automatic level control loop comprising an input for receiving an input RF signal; a level modulator, wherein the level modulator receives the input RF signal and a control signal and wherein the level modulator produces a first signal; a mixer that receives the first signal and mixes it with an LO signal to produce a second signal; a programmable attenuator that receives the second signal and produces an output signal; a level detector that monitors RF power of the output signal and produces a DC voltage proportional to the RF power; and wherein the DC voltage is received at a loop amplifier which produces the control signal.

Abstract: Techniques for controlling a gain state of a wireless receiver involve causing the wireless receiver to enter into a sleep mode; causing the wireless receiver to exit from the sleep mode and enter into a wake-up period; providing, via a multiplexer, a stored gain control state value to the wireless receiver for use during a warm-up period of the wake-up period, the stored gain control state value being previously read from a gain controller during a previous wake-up period of the wireless receiver; and after the warm-up period of the wake up period, providing, via the multiplexer, a current gain control state value from the gain controller to the wireless receiver for use during the wake up period, the current gain control state value being based on a signal level of a currently-received signal in the wireless receiver.

Abstract: A tuner includes a low noise amplifier (LNA), a first received signal strength indicator (RSSI), a mixer, an intermediate frequency (IF) filter, a second RSSI and an adjustment unit. The LNA amplifies a radio frequency (RF) signal. The first RSSI detects received signal strength indication of the RF signal and obtains a first signal strength voltage. The mixer is coupled to the LNA and down-converts the RF signal into a first IF signal according to a local oscillation frequency. The IF filter is coupled to the mixer and filters the first IF signal to obtain a second IF signal. The second RSSI detects received signal strength indication of the second IF signal and obtains a second signal strength voltage. The adjustment unit adjusts a gain of the LNA according to the first signal strength voltage and the second signal strength voltage.

Abstract: The invention provides a signal amplifying stage, used in a signal receiver. The signal amplifying stage has: a fixed-gain low noise amplifier (LNA), amplifying an input signal; a variable-gain LNA (VG-LNA) array, amplifying the input signal, including a plurality of parallel VG-LNAs, the VG-LNA array being parallel with the fixed-gain LNA; a variable-gain amplifier (VGA), being in series with the fixed-gain LNA and the VG-LNA array, for amplifying output signals from the fixed-gain LNA and the VG-LNA array to generate an output signal; an attenuator, being in parallel with a combination of the fixed-gain LNA, the VG-LNA array and the VGA, for attenuating the input signal to generate the output signal; and a control loop, coupled to the VGA and the attenuator, for detecting power levels of the output signal to enable and control the fixed-gain LNA, the VG-LNA array, the VGA and the attenuator.

Abstract: A receiving apparatus may achieve optimal RF and IF gain control while suppressing saturated amplification due to interference. The receiving apparatus includes an RF variable gain Amp that amplifies a received RF signal, a mixer that converts an output signal of the RF variable gain Amp into an IF signal, an IF variable gain Amp that amplifies the IF signal, a demodulator that demodulates an output signal of the IF variable gain Amp, and an AGC circuit. The AGC circuit sets a period of gain control for the RF variable gain Amp to be shorter than a period of gain control for the IF variable gain Amp when gains of the RF variable gain Amp and the IF variable gain Amp are controlled based on the output signal of the IF variable gain Amp.

Abstract: A radio frequency receiver includes a receiver circuit for processing RF signals, an antenna to receive millimeter wave RF signals, and an attenuator circuit, coupled between the receiver circuit and antenna. In one embodiment, the attenuator circuit may be used to determine a signal strength of the millimeter wave RF signals, compare this signal strength to a first threshold value. If the signal strength is above the first threshold value, a level of attenuation applied to the millimeter wave RF signals may then be increased.

Abstract: The settling time of a wireless receiver is reduced by providing a previously utilized gain control state value to an amplifier of a receiver front end during a warm-up portion of a wake-up period of the wireless receiver which follows a sleep period. One illustrative method includes the steps of receiving a notification signal which indicates that the wireless receiver is to be placed in a sleep mode, reading a gain control state value from a gain controller based on receiving the notification signal, storing the gain control state value in memory, providing the stored gain control state value from the memory to the wireless receiver during a warm-up period of a second wake-up period following the first wake-up period, and providing a gain control state value from the gain controller to the wireless receiver based on a signal level of a currently received signal of the wireless receiver after the warm-up period.

Abstract: In a wireless transmitter and receiver, a background calibration type analog-to-digital converter generally occupies a large area because of the phase compensating capacity of an op-amp included in a reference analog-to-digital conversion unit. Further, the calibration type analog-to-digital converter generally requires a sample and hold circuit to exclude influence of parasitic capacitance of wirings, thereby increasing power consumption. Digital calibration is performed by using, as a signal for calibration, an input signal of a digital-to-analog converter in a transmitter circuit of the wireless transmitter and receiver and inputting an output signal from the digital-to-analog converter to the analog-to-digital converter in the receiver circuit.

Abstract: A wireless communication system receiver compensates a received signal containing an IQ gain imbalance prior to performing frequency correction. The IQ gain imbalance in the signal is estimated after frequency correction, providing an IQ gain imbalance estimate for subsequent IQ gain imbalance compensation. The IQ gain imbalance estimation includes formulating a plurality of hypotheses of phase error between I and Q signal components, and taking as the actual phase error the hypothesis that yields the maximum power ratio between I and Q signal components. The maximum power ratio is differentiated with respect to the IQ imbalance estimate. The IQ gain imbalance estimate is updated as a function of its prior value(s), the maximum power ratio, and the derivative of the maximum power ratio.

Abstract: The present invention provides methods and related devices for adjusting the passband and/or cutoff frequency of a high-pass filter of an ADSL modem. A level of a received ADSL signal is compared with a predetermined signal level to provide a comparison result. A control signal is generated based on the comparison result and the passband and/or the cutoff frequency of the high-pass filter is adjusted responsive to the control signal. Devices and computer program products are also provided.

Abstract: A circuit arrangement includes two adjustable amplification devices where the signal output of the first amplification device is connected to the signal input of the second amplification device. The first amplification device has a digital input for controlling its gain and the second amplification device has an input for controlling its gain. The input for gain control in the second amplification device is connected to the input for controlling the gain of the first amplification device via a means such that a change in the gain of the second amplification device in one direction is effected by a change in gain, brought about by means of the control, in the first amplification device in the opposite direction such that the total gain remains essentially the same.

Abstract: An apparatus for controlling a gain of a transceiving device in a terminal for a communication system is disclosed. A memory stores predetermined thresholds for level-by-level gain controlling. A signal intensity detector detects an intensity value of a received signal. Comparators compare the received signal intensity value with thresholds predetermined according to the current state. A state detector detects a gain level for the current state according to the comparison results provided from the comparators. A controller updates the current state according to the detected gain level, controls a gain of the transceiving device according to the updated current state, and sets thresholds corresponding to the updated current state in the comparators.

Abstract: An input signal detecting apparatus and method in a digital receiver is provided. The input signal detecting apparatus includes an outer AGC for receiving an input signal and thereby controlling gains of RF and IF AGC amplifiers and generating an IF AGC gain value; an inner AGC for receiving the input signal and thereby generating an inner AGC gain value; and an input signal detector for receiving the input signal, a predetermined input signal power reference value, the IF AGC gain value and the inner AGC gain value and thereby generating a signal for representing a condition of stability of an input signal and a signal for representing a condition of existence of an input signal, thereby making it possible to reduce the channel information scanning time and determine a time at which an after-edge recoverer should be activated, by using the condition of existence of an input signal and the condition of stability of an input signal.

Abstract: A wireless receiver detects signals received at two or more antennas, with each antenna coupled to an input receive chain. A switch is employed to couple selected input receive chains to one or more corresponding output receive chains during listening, coarse-detection, and fine-adjustment modes. At least one channel selection filter (CSF) is employed in each output receive chain, and the receiver employs sub-ranging. During idle mode, one antenna's input receive chain is connected to two or more CSFs to detect the packet. When the packet is detected, during a coarse-adjustment mode, the CSFs are reconfigured to couple each antenna's input receive chain to a corresponding output receive chain using low-gain signals. During fine-adjustment mode, the various gains are adjusted to be either high- or low-gain to maintain signals within the dynamic range of the corresponding CSFs.

Abstract: The receiver is provided which comprises a mixer, a low pass filter coupled to the mixer and a plurality of gain controllers serially coupled to an output of the low pass filter (LPF). A plurality of analog-to-digital converters (ADCs) is coupled so that an input of a first of the ADCs is coupled to the output of the LPF. An input of each of a remaining portion of the ADCs is individually coupled to a corresponding output of each of the serially coupled gain blocks. An output path traced from the output of the LPF to an output of each of the analog-to-digital converters may be referred to as a processing path. Each processing path may comprise a gain controller and an ADC, except for the first processing path, which may have an ADC coupled directly to the output of the LPF.

Abstract: In a gain control device for packet signal receiver, a variable gain amplifier amplifies an input signal with a gain corresponding to a control voltage applied thereto, and a power detector detects output power of the variable gain amplifier. A packet detection circuit detects a packet signal based on the detected output power. A control circuit outputs the control voltage variable with the detected output power, and the control voltage is provided for the amplifier. Thus high-speed gain control is performed immediately after the start of detection of the packet signal. When the elapsed time after the start of detection of the packet signal exceeds a predetermined time, a sample-hold circuit sample-and-holds the control voltage. This control voltage is provided for the amplifier up to the end of reception of the packet signal thereafter. Thus low-speed gain control is performed to provide stable power without distorting the signal wave.

Abstract: A multi-stage amplifier is coupled with a power detector. The multi-stage amplifier includes a plurality of amplifier stages in series, with a signal path extending through them. The power detector is coupled to an interior node of the amplifier along the signal path, and is operable to sample a first signal being transmitted on the signal path. The power detector outputs a second signal reflective of a power of the first signal. In one embodiment, the interior node is in a matching network of the amplifier disposed between a first amplifier stage and a final amplifier stage of the amplifier. The second signal may be used in a feedback network to adjust an amount of amplification of the first signal by the amplifier.

Abstract: In order to rapidly control the gains of a plurality of variable gain amplifiers VGAs, each of gain control circuits is configured to determine a gain to be set therein, based on gain control information received from other gain control circuits existing in its preceding stage or stages and the signal level detected by a level detector circuit connected thereto. By carrying out such gain control, a total application gain is stabilized more quickly by gain control. Therefore, even in receiving systems that the preparation period for reception is very short, desired gain control is achieved within this period and stable data reception can be performed.

Abstract: A method for measuring a difference in DC offsets associated with different gain settings in a direct conversion receiver having a variable gain is provided. In a first phase, a set of response parameters that characterize a time-dependent system response to a known change in the DC offset is determined. Each response parameter corresponds to the response measured at a different time after the change. In a second phase, different gain settings are applied to the system and the response is measured at times corresponding to the times associated with each of the response parameters. The response parameters are then used to determine the difference in DC offsets associated with the different gain settings.

Abstract: A down converter using a C/N ratio correcting circuit of a base station for a mobile communication network includes: a first splitter for splitting an RF signal applied from an antenna; a VGA for controlling the gain of the RF signal split by the first splitter; a down converter for receiving the RF signal gain-compensated by the VGA and converting it to an IF signal; an amplifier for amplifying the RF signal split by the first splitter; a first voltage detect circuit for converting the RF signal applied from the amplifier to a voltage; a second voltage detect circuit for converting the IF signal fedback from the down converter to a voltage; and a comparator for comparing the voltage applied from the second voltage detect circuit and the voltage applied from the first voltage detect circuit and controlling the VGA.

Abstract: In a PLL circuit, and a wireless mobile station with that PLL circuit, an LPF charging constant current source, a discharging constant current source and a high-speed charging constant current source are connected to an output terminal of a phase comparator with current mode output. When a convergence frequency of the PLL circuit is low, an input voltage of a VCO is increased from OV so as to be converged by using the constant current source. However, when the convergence frequency of the PLL circuit is high, the input voltage of the PLL circuit is temporarily increased to the maximum voltage by using the constant current source. Thereafter, the input voltage is gradually dropped from the maximum voltage so as to be converged by using the constant current source.

Abstract: An automatic gain control system is provided. A signal path is configured to receive an input signal. The signal path includes a first amplifier that has a control input. A first signal level detector is coupled to the signal path, the first signal level detector having a signal level output. A gain control device having a first signal level input is coupled to the signal level output of the first signal level detector. The gain control device also has a first control output coupled to the control input of the first amplifier, and a gain control configuration input. A processor, coupled to the gain control configuration input of the gain control device, is configured to monitor operating conditions and to reconfigure the gain control device in response to changes in the operating conditions.

Abstract: A mobile communication system having an AGC (Automatic Gain Control) function includes an apparatus for adaptively controlling an output level of a local oscillator to reduce nonlinear distortion which may occur when a high-power RF signal is received or when it is necessary to transmit a high-power transmission signal. When a high-power RF signal is applied to a first stage in a receiving stage, the apparatus prevents the signal input to a reception AGC loop from being distorted by decreasing an output level of the local oscillator, which is provided to a down-converter. Further, when the output signal of a transmission stage has a high power level, the apparatus decreases the output level of a transmission AGC amplifier and instead increases the output level of the local oscillator, which is input to an up-converter located in an IF stage, so that it is possible to obtain a nonlinear distortion-reduced signal while obtaining the same output level.

Abstract: According to a disclosed embodiment, a receiver comprising a digital rotator in combination with a frequency error discriminator in a digital automatic frequency control loop is used to arrive at accurate digital values used to calibrate a local oscillation frequency. A frequency error in the oscillation frequency of a local frequency generation loop causes a change in the baseband input signal frequency. The change in the baseband input signal frequency related to the frequency error in the local frequency generation loop can be detected as a phase rotation by the frequency error discriminator. By using the digital automatic frequency control loop, the frequency error introduced by the local frequency generation is determined with accuracy. The frequency error and corresponding control bits are entered into a calibration table. The calibration table may be used to adjust the local oscillation frequency for temperature changes, pilot frequency searching, and quick paging.

Abstract: In a radio circuit (299) that forwards a signal pair (I,Q) by a first channel (291, I) and by a second channel (292, Q), a gain controller (200) monitors differences between the overall gains (GI, GQ) in the channels and corrects a gain imbalance by feeding back a gain determining control signal (W) to one of the channels. The controller has first (221-224) and second (211-214) pluralities of single-bit comparators, operating at a high sampling rate, to monitor the signal pair at the channel inputs (281, 282) and at the channel outputs (283, 284), respectively, and to provide difference signals (&Dgr;X,&Dgr;Y) to an integrator (280) that calculates the gain control signal (W) at a decimated sampling rate (FR).

Abstract: Method of obtaining a transmission gain function for an array of antennae communicating to a telecommunication terminal. The method includes determining a first weighting vector {overscore (b)}u maximizing on reception by the array a ratio (C/(Iu+Nu))u of a received signal coming from the telecommunication terminal to a noise plus interference disturbing an uplink channel, and calculating from the first weighting vector {overscore (b)}u a second weighting vector {overscore (b)}d maximizing on reception by the telecommunication terminal a ratio (C/(Id+Nd))d of a received signal coming from the array to a noise plus interference disturbing the downlink channel. The second weighting vector is in the form of a matrix product including a first noise matrix Du which is a function of a power of the first isotropic noise and/or a power of the first directional noise and a second noise matrix Dd which is a function of a power of the second isotropic noise and/or a power of the second directional noise.

Abstract: Overload distortion protection for a wideband receiver having a wideband variable gain input amplifier followed by a frequency conversion stage followed in turn by an intermediate frequency amplifier and detector to produce a measurement value in response to a signal input to the wideband variable gain input amplifier is achieved by detecting the peak power of the signal at the output of the wideband variable gain input amplifier and comparing it with the power output from the intermediate frequency amplifier and detector. If a threshold difference is exceeded, gain control signals for the wideband variable gain input and intermediate frequency amplifiers are adjusted for optimum dynamic range. If there is no range for adjusting the gain control signals, then a warning is provided to an operator to alert that the measurement value may contain distortion.

Abstract: A data portion measuring section 103 measures a reception level of a data portion of a received signal, and a pilot portion measuring section 104 measures a reception level of a pilot portion of the received signal. A comparing/selecting section 105 compares the reception level of the data portion with that of the pilot portion, and selects a higher reception level. An AGC gain value calculating section 106 calculates an AGC gain value from the higher reception level selected by the comparing/selecting section 105 and an input allowable level of A/D conversion.

Abstract: According to a disclosed embodiment, a receiver comprising a digital rotator in combination with a frequency error discriminator in a digital automatic frequency control loop is used to arrive at accurate digital values used to calibrate a local oscillation frequency. A frequency error in the oscillation frequency of a local frequency generation loop causes a change in the baseband input signal frequency. The change in the baseband input signal frequency related to the frequency error in the local frequency generation loop can be detected as a phase rotation by the frequency error discriminator. By using the digital automatic frequency control loop, the frequency error introduced by the local frequency generation is determined with accuracy. The frequency error and corresponding control bits are entered into a calibration table. The calibration table may be used to adjust the local oscillation frequency for temperature changes, pilot frequency searching, and quick paging.

Abstract: A television receiver includes a tuner for receiving either analog or digital signals. Separate analog and digital demodulators are selectively coupled to the tuner through an RF switch that is controlled by a sync detector in the output of the analog demodulator. The selected one of the demodulators develops an AGC signal that is coupled to the tuner through the RF switch. In one embodiment, a two pole RF switch is used with one pole switching the IF signal and the other pole switching the AGC signal In another embodiment, a single pole RF switch is used with the tuner signal and the AGC signal being multiplexed through the switch. This is accomplished by the provision of a high frequency path and a low frequency path between each of the RF switch and the tuner, the RF switch and the analog demodulator, and the RF switch and the digital demodulator.