Abstract: An improved complex-IF digital receiver has various improvements. The improved complex-IF digital receiver, for single or dual band applications, preferably synchronizes all of the signals to each other, which may be an integer multiple of each other. For example, the decimation filter, delta-sigma modulator, sensitivity DAC, and other circuits in the receiver can be synchronized. The delta-sigma modulator preferably includes a comparator whose input is coupled to a sensitivity DAC or synchronous dithering circuit. Ideally, the sensitivity DAC forces the comparator to trigger at every clock cycle and reduces the effect of hysteresis and offset at the input of the comparator. The receiver includes a translation circuit that translates an intermediate frequency signal to baseband, where the translation circuit preferably operates a translation ratio that is a multiple of 4.

Abstract: An elastic store circuit includes a set/reset flip-flop circuit corresponding to plural pieces of input data and an AND circuit for receiving the output of each flip-flop circuit. Upon receipt of a frame pulse indicating the head of each piece of input data, the flip-flop circuit outputs a signal to the AND circuit. The AND circuit outputs an H signal when it receives signals from all flip-flop circuits, and detects the receipt of the data having the longest delay time. According to the output signal of the AND circuit, data is read from each unit of elastic store memory.

Abstract: An orthogonal demodulating section converts the frequency of received signals to the lower range after rejecting an image band thereof by an RE filter. An image rejecting section rejects the image band of the orthogonally converted output. It allows enough of an image rejecting degree to be obtained. An A/D converter section converts the whole range into a digital signal and an orthogonal demodulating section demodulates a desirable channel by means of digital processing. Then, a channel selecting section selects and outputs the desirable channel.

Abstract: Fractional bit rate encoding in a discrete multi-tone (DMT) communication environment allows the transmission of fractional bit rates, thus maximizing the use of signal-to-noise ratio (SNR) available on each of the DMT carriers, or tones, while maintaining a constant power density over the entire frequency spectrum.

Abstract: The present invention is a system, mobile device and process. In a system, including a plurality of transmitters which transmit from at least one of the transmitters first and second complex sequences respectively from two spatially diverse antennas of the at least one transmitter to a mobile device, a method at the mobile device in accordance with the invention includes demodulating the first and second complex sequences to produce demodulated complex first and second sequences; detecting the demodulated first and second complex sequences to produce detected complex first and second sequences by multiplying respectively the demodulated first and second complex sequences with complex conjugates thereof; averaging a function of the complex detected first and second sequences to produce an averaged function; and processing the averaged function to detect a time, relative to a system time reference, of at least one peak therein resultant from the transmission of the first and second complex sequences.

Abstract: Circuitry for transmitting signals through a transformer has an output transistor and circuitry which provides a controlled current to and from the output transistor's gate, so as to charge and discharge the gate's parasitic capacitance and increase and decrease the transistor's output current in a controlled manner. Feedback can be used to sense an output signal created by the transistor and turn off current to or from the transistor's gate when the output signal has reached a desired level. The output signal can be the voltage differential produced across an output transformer, and, where the output transformer is center-tapped, it can be the voltage differential across both halves of the center tapped winding.

Abstract: A system and method for transmitting data over a channel, in which the data are categorized in at least two different categories. For example, the data are categorized according to the effect on perceived degradation on the data when error mitigation is performed on the data. Corrupted data of the first category are replaced using a first replacement method, such as retransmission and forward error correction. The corrupted data of the second category are replaced using a second replacement method different from the first replacement method, e.g., error mitigation or interpolation.

Abstract: An apparatus includes two antennas and a receiving device working with space diversity. The receiving device receives signals modulated with complex time spreading coefficients produced by a base station. The receiving device includes demodulation branches which have code inputs. To avoid signals coming from the antennas being digitally coded in an independent manner, a mixer circuit shifts the phase of the signals of one of the channels, whereas the code inputs of one of the branches receive the spreading code and the inputs of at least one other branch receive the conjugate spreading code.

Abstract: A phase detector generates a phase dependent control signal according to the phase relationship between a first and second clock signal. The phase detector includes first and second phase detector circuits receiving the first and second clock signals and generating select signals having duty cycles corresponding to the phase relationship between the clock edges of the first and second clock signals. The phase detector also includes a charge pump that receives select signals from the phase detector circuits and produces an increasing or decreasing control signal when the first and second clock signals do not have the predetermined phase relationship, and a non-varying control signal when the first and second clock signals do have the predetermined phase relationship. The control signal may be used to adjust the delay value of a voltage-controlled delay circuit in order to adjust the phase relationship between the first and second clock signals to have a predetermined phase relationship.

Abstract: A signal extraction method is provided. In the method, signals are extracted by using K beam forming parts, wherein K is a natural number equal to or more than 2, and received signals from a plurality of antennas are applied to each beam forming part. The method includes the steps of: the received signals being processed by each beam forming part successively; a first beam forming part extracting a first signal from the received signals; and a kth beam forming part canceling, from the received signals, signal components which are extracted by beam forming parts from the first beam forming part to a (k?1)th beam forming part so as to extract a kth signal, wherein 2?k?K.

Abstract: A communication apparatus that is selectively connected to a central communication apparatus. The communication apparatus transmits CLR signals to the central communication apparatus that indicates a plurality of capabilities list of the communication apparatus, and also requests that the central communication apparatus transmit a capabilities list of the central communication apparatus to the communication apparatus. Upon receipt of a CL signals from the central communication apparatus that indicates a capabilities list of the central communication apparatus, the communication apparatus transmits ACK signals or MS signals to the central communication apparatus that designates a particular communication mode.

Abstract: A symbol combining method in a Rake receiver, which relates to a method for combining the demodulated multi-path signals in a demodulation process of a code division multiple access communication system. The symbol combining method, a Rake receiver using the symbol combining method and a method for driving the Rake receiver, remarkably reduce a hardware complexity of a FIFO register used to regulate a timing synchronization of each finger in Rake receiver by using a new algorithm in a combining process when a CDMA communication system combines a plurality of multi-path signals therebetween. Whereas a conventional combining algorithm uses an individual FIFO register every finger so as to adjust a timing synchronization of each symbol before combining a demodulated symbol, the inventive combining algorithm performs a symbol combining operation as well as a timing synchronization of a symbol at the same time, and performs a combining action by using only one FIFO register irrespective of the number of fingers.

Abstract: Digital modem for data exchange between a data distribution unit (2) and at least one receiver (3, 4) which can be connected to the digital modem (1) with: a user-data forward signal path (17) for the transmission of user data from the television-data distribution unit (2) to the receiver (3, 4) over broadband user-data forward transmission channels, a backward signal path (42) for the transmission of television-receiver control data from the receiver (3, 4) to the data distribution unit (2) over narrowband backward transmission channels; and with a control-data forward signal path (27) for the transmission of narrowband control data or user data from the data distribution unit (2) to the receiver (3, 4) over narrowband forward transmission channels, it additionally being possible for broadband user data to be transmitted over the control-data forward signal path (27) from the data distribution unit (2) to the receiver (3, 4).

Abstract: A constrained-envelope digital communications transmitter (10) places constraints on the envelope of a spectrally constrained, digitally modulated communication signal (42) to lower peak-to-average power ratio without allowing significant spectral regrowth. A communication signal (14,42) is applied to a plurality of cascade-coupled constrained-envelope generators (50). Each constrained-envelope generator (50) detects overpeak events (52) and configures corrective impulses (54) for the overpeak events (52). The corrective impulses (54) are filtered into shaped pulses (88) that exhibit a constrained spectrum and combine with the communication signal (14, 42) to reduce an unwanted signal peak. Trailing portions (92) of the shaped pulses (88) are fed-back and combined with the communication signal (14,42) so that future overpeak events (52) are identified after compensation is made for the influence of the trailing portions (92) of any recently past shaped pulses (88) on the communication signal (14,42).

Abstract: A first communication device that is connectable to a second communication device. The first communication device includes a negotiation data transmitter that transmits negotiation data with a first group of frequencies to the second communication device. The first communication device includes a negotiation receiver that receives negotiation data with a second group of frequencies from the second communication device. The first group of frequencies and the second group of frequencies belong to mutually different bands. This abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

Abstract: A superhet receiver with quadrature IF and improved demodulator is configured to recover a modulated signal from a low IF in a radio receiver. A superhet receiver receives a FM radio-frequency signal, converts the input RF signal to an in-phase IF signal and an IF signal in phase quadrature to the in-phase signal, and outputs the IF signals. A plurality of monostables receive the IF signals and each monostable generates a corresponding output pulse. By combining the monostable output pulses, a complex waveform is generated. The complex waveform includes the demodulated signal and a carrier signal at a significantly higher IF. The complex waveform is filtered to recover the desired modulated signal.

Abstract: A delay device 102 sends reception signals to a subtraction device 113 after delaying it by a predetermined time. Matched filters 103-1˜103-N perform despreading operation of the reception signals. RAKE-combining devices 104-1˜104-N perform RAKE-combining operation of the signals after the despreading operation. Discrimination devices 105-1˜105-N perform hard decision of the signals after the RAKE-combining operation. A decision value buffer 107 stores the signals after the hard decision. Likelihood calculation devices 106-1˜106-N calculate likelihood of all the symbols. A likelihood buffer 108 stores calculated likelihood. A controlling part 110 controls a switch 109. A ranking decision device 111 decides a ranking based on the likelihood. A re-spreading device 112 performs re-spreading operation of a symbol with the highest likelihood ranking. And a subtraction device 113 subtracts the re-spreading result from the delayed reception signals.

Abstract: A system and method that scrambles the phase characteristic of a carrier signal are described. The scrambling of the phase characteristic of each carrier signal includes associating a value with each carrier signal and computing a phase shift for each carrier signal based on the value associated with that carrier signal. The value is determined independently of any input bit value carried by that carrier signal. The phase shift computed for each carrier signal is combined with the phase characteristic of that carrier signal so as to substantially scramble the phase characteristic of the carrier signals. Bits of an input signal are modulated onto the carrier signals having the substantially scrambled phase characteristic to produce a transmission signal with a reduced PAR.

Abstract: A differential detector generates, for each symbol, a phase difference between phase information received from a phase detector and one-symbol-delayed phase information of the received phase information. The one-symbol-delayed phase information is transferred to a differential detector, which generates, for each symbol, a phase difference between the one-symbol-delayed phase information and two-symbol-delayed phase information. The generated phase differences are fed to another differential circuit, which in turn generates, for each symbol, a difference between both received phase differences to produce phase-difference difference information. A clock regenerator circuit extracts symbol timing from the phase-difference difference information and regenerates clock signals synchronizing with the extracted symbol timing.

Abstract: A communication apparatus that is selectively connected to a central communication apparatus. A transmitter associated with the communication apparatus transmits a MR signal to the central communication apparatus. The MR signal requests the central communication apparatus to transmit a MS signal back to the communication apparatus designating a particular communication mode to be used between the communication apparatus and the central communication apparatus. In response to the received MS signal, the transmitter transmits an ACK signal or a NACK signal to the central communication apparatus.