Abstract: A receiver for spread spectrum communication decoding spread spectrum signals so as to obtain data by correlating a same received signal given to a first input of each of the convolvers constituting a correlator with two reference signals given to the other input of each of the convolvers, is disclosed, in which a phase shifter is disposed on the other input side of either one of the convolvers and the phase shifter generates one of the two reference signals having a predetermined phase difference with respect to the other.

Abstract: A spread spectrum communicating method does not use as a spreading code a normal PN code having a code length of an add number of chips in the original form, but uses a PN code having a code length of an even number of chips obtained by adding or subtracting a code of a predetermined number of chips to or from the original PN code to use it as the spreading code.

Abstract: A typewriter having an operation mode selector key so as to easily select either of two print mode settings; a first print mode setting in which print data are printed between left and right margins set by a margin set key; and a second print mode setting in which print data are printed from a left margin set by the margin set key and the carriage is returned in accordance with format data stored in a memory.

Abstract: A method for determining the initial state of shift registers constituting a modular type or simple construction type maximum length linearly occurring code sequence generator used in a spread spectrum communication system is disclosed, by which it is determined by the following equation; ##EQU1## where yj(0) is the j-th element of Y (0), andX=P X (0).

Abstract: A typewriter having an automatic erasing function, having an erasing device responsive to an erasure-start key, for effecting an erasing operation to successively erase the characters printed by a printing device, and a controller responsive to the erasure-stop key, for permitting the erasing device to interrupt the erasing operation. The typewriter has an input buffer for storing input data which is entered through a keyboard while the erasing device is operated, the typewriter. The typewriter may be arranged so that the input buffer is cleared upon operation of an erasure-stop key. The above arrangement may be adapted to erase successive words on a display device as character and space data are retrieved from a memory. In this case, a device may be provided to suspend a continuous erasing operation for a predetermined time each time the space data representative of a space between the words has been retrieved from the memory after at least one character has been erased.

Abstract: An electronic typewriter is provided with a function that the print head is moved leftward linearly when a backspace key is continuously operated after the printing paper is fed more than a preset amount, while the print head traces the printed characters when the printing paper is fed less than the preset amount. The typewriter is convenient in erasing a mistyped character on a printed line with a superscripted or subscripted character and also useful in printing new characters on the same fed printed line.

Abstract: A matrix switching apparatus for preventing a pseudo input condition caused by a detour of a signal as well as output of an erroneous signal caused by a noise intruding into an apparatus and the like, in which a plurality of key lines having a plurality of switches are arranged in the first and second directions respectively. The apparatus includes a detector for detecting an ON condition of the plurality of the switches by a time-sharing detection, a counter for counting up a number of the switches which are in the ON condition simultaneously, both totally and respectively with the key lines, a storage means for storing a first, second, third and fourth statuses which represent the condition of the switches respectively, and a controller for inverting the second status into the first status.

Abstract: A phase shifter includes first and second series-connected resistor circuits each including first and second resistors and each interposed between each one of two input terminals and each one of two output terminals, and includes capacitors each interposed between each one of medium points of the series-connected circuits and each one of two output terminals. The phase shifter also establishes a relationship of RgRl=R.sup.2 where the value of the first resistor is Rg/2, the value of the second resistor is R, and the output resistance between the two output terminals is Rl.

Abstract: A PSK demodulator, by which a first output signal obtained from a local oscillator circuit working asynchronously with respect to the carrier phase of an inputted burst PSK signal and a second output signal shifted in phase by 90.degree. with respect to the first output signal are multiplied by the inputted burst PSK signal by means of a first multiplier and a second multiplier, respectively. Each of the output signals from the first and second multipliers are compared with a first reference voltage and a second reference voltage, which is lower than the first reference voltage. The output signals are classified into 4 sorts of level signals, those which are higher than the first reference voltage and those which are lower than the second voltage; and thus the inputted burst PSK signal is demodulated by using these 4 sorts of level signals.

Abstract: A receiver includes a surface acoustic wave amplifier provided in a high frequency amplification stage and generating two outputs corresponding to acoustic waves which propagate through said amplifier in the opposite directions. One of the outputs is demodulated by a phase locked loop demodulator or by a frequency discriminator and is applied to and controls a voltage control oscillator. Frequency modulated components of an output from the voltage control oscillator is used to produce frequency modulated components of a pumping power for the surface acoustic wave amplifier.

Abstract: A PSK demodulator demodulate a PSK signal into a digital data, which PSK signal is an encoded signal comprising a carrier phase shifted by a digital signal data.

Abstract: Receiver comprising at least two output means taking out electric signals corresponding to sound waves propagating in different directions in a surface elastic wave amplifier disposed in the high frequency amplifier stage, wherein phase difference or frequency difference between outputs of said output means is detected and frequency of pumping electric power applied to said surface elastic wave amplifier is controlled in response to output thus detected.

Abstract: A receiver is provided with a surface elastic wave amplifier of a parametric amplification type within an HF amplifier unit, and with a circuit for providing pumping power for said surface elastic wave amplifier from oscillating outputs of an IF converting local oscillator of the receiver.

Abstract: A printing apparatus comprising a print wheel having a multiplicity type elements, and a detecting unit for detecting angular positions of the print wheel including its fixed home position. The apparatus further comprises a control unit which includes a first counter which stores data representative of an angular distance of a type element currently located at the printing position as measured from the home position, and a second counter which stores data representative of an angular position of a type element designated by a print signal. Both counters are operated as they receive position signals from the detecting unit.

Abstract: In a pulse generator responsive to an input pulse, use is made of a time constant circuit having a time constant for charge and a time constant for discharge considerably greater than the former. The time constant circuit is rapidly charged during presence of the input pulse in accordance with the time constant for charge, through a switching circuit kept on, while it is slowly discharged in accordance with the time constant for discharge after the switching circuit is rendered off due to disappearance of the input pulse. During charging and discharging, the time constant circuit gives a variable level to a threshold circuit for producing an output pulse when the variable level exceeds a threshold level. The output pulse lasts until the variable level is rendered less than the threshold level after disappearance of the input pulse. Additionally, the pulse generator comprises a combination of a constant current portion and a constant voltage portion to stabilize the input and output pulses.

Abstract: A gate circuit comprised of a first gate transistor normally off; a second gate transistor normally on and connected in a signal path; said first gate transistor being adapted to be turned on when a pulse is applied thereto and said second gate transistor being adapted to be turned off upon the conducting of said first gate transistor, and a limiter for holding the potential at the input of the second gate transistor lower than the potential at the output thereof.

Abstract: A noise eliminating circuit comprising means for generating a signal having a phase difference with respect to an input signal, means for simultaneously cutting off the input signal and the phase difference signal at the time when a noise is entering the circuit, means for retaining the levels of the respective signals that have developed immediately before said signals are cut off, and means for outputting a retained signal of one level by adding the same to a retained signal of the other level at a given time constant, thereby to make up for the signal interruption, preventing deterioration in tone quality caused by such signal interruption.

Abstract: A noise eliminating circuit for detecting and eliminating a noise pulse component included in an amplitude modulated wave, characterized by a circuit arrangement wherein an output of a detector circuit which is adapted to receive an input signal from an IF stage is coupled to an input of a band-pass filter through a noise amplifier; an output of said band-pass filter is coupled to an input of a pulse generator circuit; an output of said pulse generator circuit is connected to a gate circuit for stopping an audio AGC control operation and a gate circuit for eliminating a noise; an output of said noise amplifier is connected to an AGC control circuit through said gate circuit for stopping the audio AGC operation in order to apply an audio AGC control signal to said noise amplifier; and an output of said band-pass filter is connected to said AGC control circuit in order to apply a noise AGC to said noise amplifier; whereby said pulse generator circuit generates a pulse in response to the detection of the noise s

Abstract: A system for eliminating a noise from a stereo signal is disclosed comprising first and second signal paths to which an input stereo signal is applied simultaneously, storage means provided in the first signal path for storing an audio signal component, a pilot tone signal component and a sub-signal component of the stereo signal, the output of the storage means being grounded through a switch that is on when no noise exists, said switch being turned off when a noise exists in the stereo signal and extracting only the noise component by cancelling each signal component by its counterpart stored in the storage means, said noise component being phase inverted to be applied to the output of the second signal path.

Abstract: In an audio reproducing system including mixer means, intermediate frequency transformer means, first gate means and audio reproducing means following said first gate means, a noise detecting circuit comprising detector means for detecting a high frequency component of the output signal of said mixer means; amplifier means for amplifying a signal having said high frequency component from said detector means; pulse generator means for producing a pulse in response to a noise component in the output of said amplifier means; automatic gain control means for controlling the gain of said amplifier means, second gate means provided between said automatic gain control means and said amplifier means; and means for applying said pulse to said first and second gate means to operate them to thereby prevent application of said noise component to said audio reproducing means.