Abstract: For adjusting audio streaming bandwidth based on volume, a processor detects a low-volume condition for streaming audio. In response to detecting the low-volume condition, the processor communicates a request for reduced bandwidth for the streaming audio.

Abstract: A method of detecting a fault in an induction machine having one or more windings arranged to draw current at a supply frequency, the method including: performing a process of judging whether a respective sideband of one or more selected harmonics of the supply frequency exists at a predetermined fault frequency in a signal in the one or more windings; and determining that a fault has occurred if the judgement is positive; wherein in the judging process each of the selected harmonics of the supply frequency is a harmonic frequency of the supply frequency other than the supply frequency itself.

Abstract: Systems and method for improving performance of a radio frequency system are provided. One embodiment describes a radio frequency system, which includes an antenna that wirelessly transmits analog electrical signals at a desired transmission frequency; a feedback receiver that determines a feedback signal, which includes a portion of a transmitted analog electrical signal via a coupler; and a controller that determines location and magnitude of spurious emissions transmitted at frequencies other than the desired transmission frequency by comparing the feedback signal with a desired signal, in which the desired signal includes a digital electrical signal that does not contain noise introduced by the radio frequency system; and instructs the radio frequency system to adjust operational parameters used to transmit the analog electrical signals when the magnitude of the spurious emissions exceeds a spurious emissions limit at the determined location.

Abstract: A method, a user equipment (UE) and a communication system are provided. In the disclosure, a UE configured with multiple carriers determines whether a first, a second, and a third conditions are met, and then determines whether resources allocated for the UE on the carrier are sufficient or not accordingly. The first condition defines that the UE is transmitting as much scheduled data as allowed by a current service grant on the carrier. The second condition indicates that the UE has enough transmission power available to transmit data at higher data rate on the carrier. The third condition indicates total buffer data requires more than a preconfigured time period to be transmitted through the carrier together with at least one of other carriers among the multiple carriers.

Abstract: A User Equipment (UE), a method for determining a resource, a method for reporting a resource, and a system for distributing a resource are provided. The method for determining a resource includes: if transmission data on the carrier reaches maximum transmission data supported in a scope allowed by Service Grant (SG), and a transmission power of the UE is capable of improving a data transmission rate of the carrier, and the carrier and the other one carrier of the dual carriers are incapable of completing transmitting total buffer status data in the same delay period, determining that a resource distributed to a UE on one carrier of dual carriers of the UE is insufficient; otherwise, determining that the resource distributed for the UE on the carrier is sufficient. Therefore, a solution for reporting the resource of the dual carriers is provided, so as to improve a network performance.

Abstract: There is described a time-to-digital conversion scheme using an arrangement of delay elements based Time-to-Digital Converter, TDC (20), wherein dithering is built in the digital domain and introduced in the analog domain as a modulation of a supply voltage (TDC-supply) supplying delay elements of the TDC, each having a propagation delay which exhibits a dependency to their supply voltage.

Abstract: The present invention discloses a method for service data transmission, a receiver, a mobile terminal, a transmitter and a base station. In the above method, a receiver of a mobile terminal receives a control signal sent by a base station, wherein the control signal is used for indicating more than one subcarriers allocated to the mobile terminal and the more than one subcarriers are used for service data transmission; it is judged whether the difference between the highest frequency FREHigh and the lowest frequency FRELow in the more than one subcarriers exceeds a threshold value THB; if not exceed, then the receiver receives service data using a narrowband mode, otherwise receives the service data using a broadband mode.

Abstract: A signal transmitting apparatus includes a signal distributor, a frequency converter, and a frequency synthesizer. The signal distributor is configured to baseband signals corresponding respectively to a plurality of frequency band. The frequency converter is configured to convert each of the distributed baseband signals into one of a positive frequency signal and a negative frequency signal according to the frequency band. The frequency synthesizer is configured to synthesize the positive frequency signal and the negative frequency signal to generate a transmission signal. Herein, the positive frequency signal and the negative frequency signal are signals included in one predetermined intermediate frequency band.

Abstract: A frequency and data synchronization control system through the 8VSB SFN DTx modulation prevents the deterioration of the digitally broadcasted receiving sensitivity caused by a discrepancy of the frequency or data between the receiver of the digital broadcasting signal and the distributed translator or between distributed translators.

Abstract: An embodiment of the invention provides an electronic device. The electronic device includes a digital-to-analog converter (DAC), a transmitter front-end (TX FE), an amplifier, an analog-to-digital converter (ADC), and a swap circuitry. The TX FE has a first and a second input end coupled to a first and a second output end of the DAC, respectively. The ADC has a first and a second input end coupled to a first and a second output end of the amplifier, respectively. The swap circuitry is configured to couple the first and second output ends of the DAC to a first and a second input end of the amplifier in a normal state, respectively, and couple the first and second output ends of the DAC to the second and first input ends of the amplifier in a swapped state, respectively.

Abstract: An apparatus for transmitting data in a communication system includes: a processor configured to process broadcasting data regarding various types of digital broadcasts to be provided to users; an S/P converter configured to convert additional data of the broadcasting data into a parallel type; a phase selector configured to generate a phase selection value using additional data bits, except for a first additional data bit, of the converted parallel-type additional data; a sequence generator configured to generate a sequence using the first additional data bit and the phase selection value; and an adder configured to couple the generated sequence with the processed broadcasting data.

Abstract: A cosite interference cancellation system is provided for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath. The cosite interference cancellation system and associated method advantageously provide improved signal rejection by continuously controlling (adjusting) a matching time delay to reduce cosite interference.

Abstract: When the change speed is instructed, without changing value of a suppressing vibration flag set to value 1 as initial value, a fast fill as the preparation of a brake to be engaged when the change speed is executed and low pressure standby of hydraulic pressure to set the brake in a half-engaged state. Then the suppressing vibration flag is set to value 0 when a predetermined time passed since the change speed is instructed, a sum of a drive torque required for driving and a suppressing vibration torque, which is in the same direction as suppressing rotational fluctuation of a drive shaft, is output from a motor when the suppressing vibration flag is set to value 1.

Abstract: A single sideband mixer is constructed with digital logic elements such as T-type flip-flops and inverters and with FETs, and the resulting mixer circuit simultaneously improves control over the frequency resolution, noise floor and operating frequency range. The use of this group of elements also allows the mixer circuit to be easily realized in an integrated circuit.

Abstract: A phase locked loop (PLL) a phase detector, a charge pump, a loop filter, a controlled oscillator, and a feedback divider. The phase detector is coupled to produce a difference signal based on a difference between phase of a reference oscillation and phase of a feedback oscillation. The charge pump is coupled to convert the difference signal into an up-signal or a down signal. The loop filter coupled to filter the up signal or the down signal to produce a control signal. The controlled oscillator is coupled to generate an output oscillation based on the control signal. The feedback divider is coupled to generate the feedback oscillation from the output oscillation based on a divider value. The loop filter includes a first resistor-capacitor circuit and a second resistor-capacitor circuit. The first resistor-capacitor circuit is calibrated using a first calibration technique and the second resistor-capacitor circuit is calibrated using a second calibration technique.

Abstract: A VSB communication system or transmitter for processing supplemental data packets with MPEG-II data packets includes a VSB supplemental data processor and a VSB transmission system. The VSB supplemental data processor includes a Reed-Solomon coder for coding the supplemental data to be transmitted, a null sequence inserter for inserting a null sequence to an interleaved supplemental data for generating a predefined sequence, a header inserter for inserting an MPEG header to the supplemental data having the null sequence inserted therein, a multiplexer for multiplexing an MPEG data coded with the supplemental data having the MPEG header added thereto in a preset multiplexing ratio and units. The output of the multiplexer is provided to an 8T-VSB transmission system for modulating a data field from the multiplexer and transmitting the modulated data field to a VSB reception system.

Abstract: Provided is a power supply circuit capable of operating with low noise and low power consumption. In a power supply circuit, a power level control signal Pa for controlling a power level of a power amplifier, and an internal current control signal Pb which is a result of smoothing the power level control signal Pa at predetermined time intervals, are inputted to an operational amplifier. The operational amplifier amplifies the power level control signal Pa, and controls an internal current thereof such that the internal current has a similar characteristic to that of the internal current control signal Pb. A power transistor amplifies an output of the operational amplifier, and supplies a voltage to the power amplifier.

Abstract: Communication with less noise is to be performed. A voltage value control signal functioning as an instruction to change the voltage value supplied from a voltage converting section to an LFI is output from a CPU. A driving section for the LFI outputs the control signal at 125 kHz that drives an FET circuit section according to the voltage value supplied from an ECU. The FET circuit section outputs the driving current for an antenna under the control of the driving section. A connecter terminal that connects to a harness is connected to a connecter terminal for GND connection along with the GND terminal of the voltage converting section. A connecter terminal that connects to a harness is connected to a connecter terminal for GND connection along with the GND terminal of the FET circuit section.

Abstract: A cosite interference cancellation system is provided for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath. The cosite interference cancellation system and associated method advantageously provide improved signal rejection by continuously controlling (adjusting) a matching time delay to reduce cosite interference.

Abstract: A VSB communication system or transmitter for processing supplemental data packets with MPEG-II data packets includes a VSB supplemental data processor and a VSB transmission system. The VSB supplemental data processor includes a Reed-Solomon coder for coding the supplemental data to be transmitted, a null sequence inserter for inserting a null sequence to an interleaved supplemental data for generating a predefined sequence, a header inserter for inserting an MPEG header to the supplemental data having the null sequence inserted therein, a multiplexer for multiplexing an MPEG data coded with the supplemental data having the MPEG header added thereto in a preset multiplexing ratio and units. The output of the multiplexer is provided to an 8T-VSB transmission system for modulating a data field from the multiplexer and transmitting the modulated data field to a VSB reception system.

Abstract: The present invention provides an RF transmission leakage mitigator for use with a full-duplex, wireless transceiver. In one embodiment, the RF transmission leakage mitigator includes an inversion generator configured to provide an RF transmission inversion signal of an interfering transceiver RF transmission to a receiving portion of the transceiver thereby creating a residual leakage signal. Additionally, the RF transmission leakage mitigator also includes a residual processor coupled to the inversion generator and configured to adjust the RF transmission inversion signal of the interfering transceiver RF transmission based on reducing the residual leakage signal to a specified level.

Abstract: Provided are a digital IF wireless transmitter, an RF modulator, and an RF modulating method.

Abstract: A DC offset cancellation circuit used for compensating a carrier leak at an output signal of a modulator has a sign extraction unit for extracting sign of an information signal which is applied to the modulator, an envelope detecting unit for performing envelope detection on the output signal of the modulator to output the resulting envelope, a slope detecting unit for performing polarity detection on the slope of the envelope; and a signal processing unit for generating a DC offset cancellation signal for compensating the carrier leak based on the result of the sign extraction and the result of the polarity detection. The signal processing unit preferably calculates the DC offset cancellation signal by multiplying the sign of the information signal by the polarity of the slope of the envelope and accumulating the result of multiplication.

Abstract: The disclosure can provide methods and systems for autocalibrating a transceiver. The method can include upconverting a bandpass input signal by mixing the bandpass input signal with a first local oscillator signal to form an initial transmitter signal. The initial transmitter signal can be looped back to a receiver and downconverted with a second local oscillator signal having a frequency that is different from the first local oscillator to form an intermediate frequency signal. At least one of a gain and a phase of the transmitter can be adjusted based on a transmitter image sideband of the intermediate frequency signal to generate a calibrated transmitter signal having minimized transmitter image sideband.

Abstract: A transmitter includes a first amplifier to amplify an in-phase oscillator signal to produce an in-phase mixing signal and a second amplifier to amplify a quadrature-phase oscillator signal to produce a quadrature-phase mixing signal. A first mixer mixes the in-phase mixing signal with a first information signal to produce a first output signal. A second mixer mixes the quadrature-phase mixing signal with a second information signal to produce a second output signal. The first output signal and an inverted second output signal are summed to produce a transmitter output signal that includes an image signal caused by a phase imbalance between the in-phase and quadrature-phase mixing signals. An image monitor monitors the image signal and reduces or eliminates the phase imbalance by independently adjusting a phase of the in-phase mixing signal and/or a phase of the quadrature-phase mixing signal. Consequently, a power of the image signal is reduced or eliminated.

Abstract: Frequency pattern generator (1, 101, 201) for generating frequency pulses, said generator having a first local oscillator unit (2-1, 121, 221) for generating a first radio frequency carrier frequency signal (LO1), at least one second local oscillator unit (2-2, . . . 2-N, 122, 222) for generating at least one second radio frequency carrier frequency signal (LO2), a switching device (3, 103, 203) for passing on one of the radio frequency carrier frequency signals (LO1, LO2) or a zero signal (DC) in a manner dependent on a control signal (CTR), and a mixing stage (9, 109, 209, 212, 309) for mixing the signal (LO) that has been passed on by the switching device (3, 103, 203) with a mixing frequency signal (LF) to form a pulsed output signal (RFOUT), the pulsed output signal (RFOUT) having frequency pulses at a respective frequency (f1, . . . f8) and length (Tp) in a manner dependent on the control signal (CTR).

Abstract: Single sideband (SSB) mixers and methods of extracting a SSB signal, which are capable of outputting a single frequency using a plurality of mixers and a local oscillating frequency without having to implement phase-shifting. In one embodiment, a single sideband (SSB) mixer comprises a first mixer and a second mixer, wherein the first and second mixers multiply an input IF (intermediate frequency) signal by a local IF signal having the same frequency of the input IF signal; a band-pass filter which passes upper sideband signal output from the first mixer; a third mixer which multiplies the upper sideband signals output from the band-pass filter by a LO (local oscillating) signal; a fourth mixer which multiplies the signals output from the second mixer by the LO signal; and a subtraction device that subtracts output signals of the third mixer from output signals of the fourth mixer.

Abstract: The present invention includes a digital quadrature rate converter and an oversampling interpolator, which are used to receive digital quadrature modulation data at one clock rate and to provide oversampled digital quadrature modulation data at a higher clock rate. Rate conversion and oversampled interpolation are used to accommodate systems with multiple clock frequencies and to generate modulation signals with low distortion. Some embodiments of the present invention add timing control to the oversampled interpolation. Some embodiments of the present invention may combine the rate conversion, oversampled interpolation, and timing control operations into a single digital circuit.

Abstract: A VSB communication system or transmitter for processing supplemental data packets with MPEG-II data-packets includes a VSB supplemental data processor and a VSB transmission system. The VSB supplemental data processor includes a Reed-Solomon coder for coding the supplemental data to be transmitted, a null sequence inserter for inserting a null sequence to an interleaved supplemental data for generating a predefined sequence, a header inserter for inserting an MPEG header to the supplemental data having the null sequence inserted therein, a multiplexer for multiplexing an MPEG data coded with the supplemental data having the MPEG header added thereto in a preset multiplexing ratio and units. The output of the multiplexer is provided to an 8T-VSB transmission system for modulating a data field from the multiplexer and transmitting the modulated data field to a VSB reception system.

Abstract: A circuit and method for supplying an electronic circuit with a direct supply voltage using high frequency antenna signals. The method includes producing a primary direct voltage equal to a fraction of the supply voltage using at least one antenna signal, producing at least two pumping signals having a frequency lower than the frequency of the antenna signals by means of an oscillator electrically powered by the primary voltage and boosting the primary voltage by means of a charge pump driven by the pumping signals, to obtain the supply voltage.

Abstract: An IF receiver receives a tapped portion of a modulated communication signal. A processor, local with respect to the IF receiver, receives an interrupt from a main processor instructing it to evaluate the power levels of desired and undesired components of the communication signal. The interrupt may be sent for a variety of reasons, such as according to a predetermined schedule, or in response to changes in a communication network, such as new equipment installation and temperature changes. The local processor instructs the IF receiver to tune it's LO so that the evaluation range of the receiver and feedback loop to parameter-adjustable components includes the frequency, or frequencies, of a specified signal component. The local processor evaluates the power level of the specified signal component. Based on the evaluation, the local processor instructs parameter-adjustable signal processing components to alter parameters to optimize characteristics of the communication signal for transmission.

Abstract: A method for single side band transmissions begins by mixing, in a current domain, an in-phase component of outbound formatted data with an in-phase component of a local oscillation to produce a first mixed signal. The method continues by mixing, in the current domain, a quadrature phase component of the outbound formatted data with a quadrature component of the local oscillation to produce a second mixed signal. The method continues by summing the first and second mixed signals to produce a radio frequency signal. The method continues by amplifying the radio frequency signal prior to transmission.

Abstract: A VSB communication system or transmitter for processing supplemental data packets with MPEG-II data packets includes a VSB supplemental data processor and a VSB transmission system. The VSB supplemental data processor includes a Reed-Solomon coder for coding the supplemental data to be transmitted, a null sequence inserter for inserting a null sequence to an interleaved supplemental data for generating a predefined sequence, a header inserter for inserting an MPEG header to the supplemental data having the null sequence inserted therein, a multiplexer for multiplexing an MPEG data coded with the supplemental data having the MPEG header added thereto in a preset multiplexing ratio and units. The output of the multiplexer is provided to an 8T-VSB transmission system for modulating a data field from the multiplexer and transmitting the modulated data field to a VSB reception system.

Abstract: A VSB communication system or transmitter for processing supplemental data packets with MPEG-II data packets includes a VSB supplemental data processor and a VSB transmission system. The VSB supplemental data processor includes a Reed-Solomon coder for coding the supplemental data to be transmitted, a null sequence inserter for inserting a null sequence to an interleaved supplemental data for generating a predefined sequence, a header inserter for inserting an MPEG header to the supplemental data having the null sequence inserted therein, a multiplexer for multiplexing an MPEG data coded with the supplemental data having the MPEG header added thereto in a preset multiplexing ratio and units. The output of the multiplexer is provided to an 8T-VSB transmission system for modulating a data field from the multiplexer and transmitting the modulated data field to a VSB reception system.

Abstract: A transmitter shifts a baseband data signal having a bandwidth of 2?M using a tone signal having a frequency ?M, which centers a sideband of the data signal at zero frequency. The transmitter then filters the shifted signal to filter out the non-centered sideband, and then adds the tone signal to form a composite signal. The transmitter upconverts the composite signal during a first operational mode using a RF signal having a frequency ?C equal to a center frequency of a channel. In a second operational mode, the transmitter upconverts a DC level using the same RF signal. The upconverted DC level can be used as a continuous wave carrier signal having a frequency ?C. The transmitter has a single RF oscillator to output both a SSB signal centered at frequency ?C during the first mode and a carrier signal of frequency ?C during the second mode.

Abstract: An apparatus and method for generating an intermediate frequency (IF) to be transferred to a single sideband (SSB) generator which generates carriers using one local oscillator (LO) signal and at least two IF signals that are received. A group signal is generated which includes a non-phase-shifted signal and a phase-shifted signal to a predetermined value with respect to each IF. One of the group signals is selected and transferred to the SSB generator. Accordingly, the SSB generator performs the phase shift on the LO signal alone.

Abstract: A time division duplex (TDD) single sideband (SSB) transceiver includes a transmitter adapted to input an analog audio signal, sample the analog audio signal, and to output an SSB frequency shift keyed (FSK) signal corresponding to the analog audio signal, the SSB FSK signal including analog information. A receiver is adapted to switch between receiving one of an upper sideband and a lower sideband of an external SSB signal.

Abstract: A chopper-direct-conversion (CDC) radio receiver includes a phase-alternating mixer receiving an antenna input signal and at least one local oscillator signal and generating a double sideband signal in a single mixing step. The phase-alternating mixer may be implemented by two parallel mixers each mixing the input signal with one of two local oscillator signals and an adder receiving and summing outputs from the two parallel mixers, by a track-and-hold circuit sampling the input signal based upon the local oscillator signal, or by a window averaging circuit averaging the input signal across a period of the local oscillator signal. The CDC architecture is suitable for fabrication on a single chip and offers solutions to virtually all problems found in conventional direct-conversion receivers.

Abstract: An SSB radio communication system and radio apparatus applicable to ultra high frequencies such as a VHF band and UHF band. In the transmitting side, a carrier wave is amplitude modulated by modulation input signals which comprise a constant amplitude, sine wave shaped reference pulse having a predetermined width and period and a sine wave shaped modulation pulse signal having an amplitude representing two- or multi-value digital values having the same width as the reference pulse signal and which are formed based on the amplitude of the reference pulse signal, and the modulated pulse signals are transmitted on a single side band, while in its receiving side the gain of received signals is automatically adjusted based on the reference pulse signal that is the value of the peak of the received signals.

Abstract: A transmitter upconverts a SSB data signal during a first operational mode using a RF upconverting signal having a frequency that is offset from a center frequency of a channel (?C) by an amount that depends on the data signal's SSB bandwidth (?M). In a second operational mode, the transmitter upconverts a tone signal having a frequency ?M using the same RF upconverting signal. The upconverted tone signal can be used as a continuous wave (CW) carrier signal having a frequency ?C. The transmitter has a single RF oscillator to output both a SSB signal centered at frequency ?C during the first mode and a carrier signal of frequency ?C during the second mode.

Abstract: A sinusoidal RF carrier is modulated for the transmission of digital binary data streams through the amplitude suppression of carrier wavelets. These wavelets are defined between zero crossover positions representing zero energy locations. This modulation is accomplished when the carrier is slightly amplitude modulated with a modulation signal that is equal in frequency to the carrier itself and the modulation always begins or ends upon the exact zero voltage crossing point of the RF cycle phase. The modulation is applied as a slight shift of the amplitude of any single cycle, each cycle representing a single bit of data. A single cycle of RF will either represent a “1” or “0” depending upon the amplitude of the cycle, relative to other adjacent cycles in the same carrier.

Abstract: The system for recovering symbol timing offset and carrier frequency error from an orthogonal frequency division multiplexed (OFDM) signal includes a receiver circuit for receiving an OFDM modulated signal representing a series of OFDM symbols, and providing a received signal to an output thereof. A peak development circuit is included for developing a signal having a plurality of signal peaks representing symbol boundary positions for each received OFDM symbol, where each of the signal peaks is developed responsive to an amplitude and phase correspondence produced between the leading and trailing portions of each of the received OFDM symbols. The system includes a circuit for enhancing the signal peak detectability, which includes a circuit for additively superimposing and then filtering the signal peaks, to produce an enhanced signal peak having an improved signal-to-noise ratio.

Abstract: An RF cable-less interconnect arrangement couples a diplexer to a radio transceiver by providing each of the transceiver and the diplexer by means of respective pairs of RF transmission and receiver channel connectors. The two sets of connectors are supported at a prescribed spatial separation for blind-mating RF connectivity for either of two orientations and translation (insertion) of the diplexer into the radio. Eliminating lossy and relatively fragile RF cable, that would otherwise occupy space within the radio's housing, and require installation by a skilled technician during assembly of the radio, allows the customer to easily change the radio's frequency plan by simply removing, rotating and reinserting the diplexer.

Abstract: A polar loop transmitter circuit arrangement includes a circuit input, a circuit output, a controllable signal source, a modulator connected between the signal source and the output, a first amplifier having its input connected to the circuit input, a second amplifier having its input connected to the circuit output, and a comparator. Each amplifier preferably includes respective amplitude detector and signal modifier portions connected in series between their respective inputs and outputs. An output of each of the amplifiers is connected to a respective input of the comparator, and an output of the comparator is connected to a control input of the modulator. The amplifiers may each be characterized by transfer functions that are generally logarithmic. Each amplifier's signal modifier portion may further include an analog-to-digital converter, a digital signal modifier, and a digital-to-analog converter.

Abstract: The invention provides an apparatus and procedure for radio transmission of information using a middle channel, a first side channel and a second side channel. The transmitted middle channel is FM-modulated by a suitable frequency. A signal symmetrically amplitude-modulated with respect to the center frequency of the middle channel is generated, and a first amplitude-modulated single side band (LSB) and a second amplitude-modulated single side band (USB) are formed from the amplitude-modulated signal. The first single side band (LSB) is modulated by the information in the first side channel to form two side bands for the first single side band, and the second single side band (USB) is modulated by the information in the second side channel to form two side bands for the second single side band. The middle channel FM signal, the modulated first single side band (SSB) and the second modulated single side band (SSB) are then combined in a combiner for simultaneous transmission of all three channels.

Abstract: The radio resource management server 1 receives radio link quality information measured by the radio base station 2 and radio link quality information measured by the radio base station 3 and thus detects the occurrence of interference. Upon the occurrence of the interference, the transmission power of the radio base station causing the occurrence of interference is controllably reduced to suppress the interference. In the method of controllably varying the transmission power of a radio base station, depending on the number of radio terminals or traffic volume, oscillation of a service area occurs. However, according to the present invention, the transmission power is changed on the occurrence of interference, without depending on the number of radio terminals or traffic volume, so that the area oscillation does not occur after the transmission power has been once stabilized.

Abstract: A single side band transmitter having reduced DC offset includes a current source modulation module, a current mirror module, a 1st mixing module, a 2nd mixing module, a summing module, and a power amplifier. The current source module is operably coupled to modulate, in accordance with a modulation protocol (e.g., FSK) data to produce an in-phase current component and a quadrature current component. The current mirror module is operably coupled to mirror the in-phase current component to produce a mirrored in-phase current component and is also operably coupled to mirror the quadrature current component to produce a mirrored quadrature current component. The 1st mixing module is operably coupled to mix the mirrored in-phase current component with an in-phase current component of a local oscillation to produce a 1st mixed current signal.

Abstract: An apparatus and method for transmitting envelope modulated data signals on a Radio Frequency (RF) carrier system, which produces high error performance through remodulation of the data signals onto an RF carrier are provided. The apparatus includes a transmit chain where, the data signal is input to a mixer to create upper and lower sidebands of the data signal. A low pass filter removes the upper sideband and passes the lower sideband to a frequency modulation (FM) modulator which modulates an RF carrier with the lower sideband. The apparatus also includes a receiver chain that has an FM receiver which receives the FM RF carrier signal transmitted by the transmit chain and recovers the lower sideband, which is then input to a multiplier to again generate upper and lower sideband signals. A bandpass filter removes the lower sideband and passes the upper sideband as a received envelope modulated data signal.

Abstract: The system for recovering symbol timing offset and carrier frequency error from an orthogonal frequency division multiplexed (OFDM) signal includes a receiver circuit for receiving an OFDM modulated signal representing a series of OFDM symbols, and providing a received signal to an output thereof. A peak development circuit is included for developing a signal having a plurality of signal peaks representing symbol boundary positions for each received OFDM symbol, where each of the signal peaks is developed responsive to an amplitude and phase correspondence produced between the leading and trailing portions of each of the received OFDM symbols. The system includes a circuit for enhancing the signal peak detectability, which includes a circuit for additively superimposing and then filtering the signal peaks, to produce an enhanced signal peak having an improved signal-to-noise ratio.

Abstract: In the broadcast band having a plurality of channels allocated therein, by using high-side injection and low-side injection as described herein, the noise introduced into the channel by the local oscillator signal can be minimized. The local oscillator signal in combination with the intermediate frequency determines the frequency of the channel signal being produced by the transmitter. The selected high-or low-side injection determines whether the bulk of the power is introduced into the combination frequency signal (i.e., the channel) above or below the local oscillator frequency, thereby moving the local oscillator frequency outside the broadcast band. The non-selected sideband is even further outside broadcast band.