Abstract: To prevent variation of a transmission band characteristic which is caused by variation of operational conditions (e.g., temperature in the rectification feedback amplification) in a system with large extraband attenuation for sharply cutting off the transmission band in each channel of the communication system including plural narrow band channels allotted close to each other, rectification feedback is effected through through an adaptive filter. A band characteristic of the adaptive filter is varied in response to the variation of operational conditions including temperature, while data processing is rapidly effected through digital signal processing. Consequently, even if the communications in each channels are intermittently repeated, each time the communication is reopened, the desired transmission band characteristic can be instantly fixed, so as to prevent the disturbance of stable operation by adjudicating the interference through data correlation.

Abstract: A highspeed scanning type radio receiver is disclosed which prevents an erroneous interruption of a scanning operation caused by high frequency noises produced from a clock oscillator and a local oscillator circuit employed therein. The highspeed scanning type radio receiver includes a highspeed clock oscillator, a lowspeed clock oscillator, and a clock switching circuit for switching these highspeed clock oscillator and lowspeed clock oscillator to be connected to a CPU. Normally, a searching operation is carried out by supplying the highspeed clock to the microcomputer. When a reception signal is detected in a certain channel, the highspeed clock is changed into the lowspeed clock to be supplied to the microcomputer, whereby a reception signal is again detected. When no reception signal is detectable, the microcomputer recognizes that the detection of the reception signal under operation at the highspeed clock is caused by high frequency noises, and commences a searching operation of the next channel.

Abstract: For accurately detecting a desired laser signal without being affected by ambient noise light pulse, a laser signal receiving apparatus, which receives a light pulse transmitted from a laser transmitter, includes a light receiving section having a photo-electric converter for converting a light pulse into an electric pulse signal, a pulse-width detecting section for detecting a pulse-width of the pulse signal derived from the light receiving section and a controlling section having a counter port supplied with the pulse signal and a pulse-width detector port supplied with an output of the pulse-width detecting section, so as to count only the pulse signal having a predetermined pulse-width, based on an output of the pulse-width detecting section.

Abstract: An automatic frequency transfer and storage method is disclosed in a scanning receiver having a channel memory having a plurality of storage locations for storing frequency numbers corresponding to frequencies. In the preferred embodiment, the storage locations are grouped into channel banks. Each storage location is identified with a channel number and each channel bank is identifed with a channel bank identifier. A source channel number and either a destination channel number or destination channel bank identifier are specified. A controller searches the specified channel bank for a clear storage location. In either case, the controller displays the pertinent frequency transfer information and the transfer is executed upon confirmation, and the source storage location is cleared.

Abstract: A radio communication receiving device performs prescribed operations upon detecting a frequency modulation preamble signal consisting of a series of alternating logical values. The device includes a low-pass filter that is connected to an output of a receiver that detects the frequency modulation signal and outputs an analog base band signal, and which has a numerical cutoff frequency value that does not exceed half the bit rate of the preamble, a comparison circuit that is connected to the output of the low-pass filter and compares an output voltage of the low-pass filter with prescribed threshold values, and a determining circuit that determines a preamble has been detected when the comparison by the comparison circuit indicates that an absolute value the low-pass filter output voltage does not exceed a prescribed threshold value for a prescribed time period.

Abstract: A low cost antenna assembly is disclosed which is formed from a flexible wire and a pair of suction cups for supporting the wire in a substantially linear fashion. A feed line couples the wire antenna to a receiver. Further, a method for fabricating the antenna is disclosed.

Abstract: Upon receipt of address data which matches one of a given plurality of capcodes, this pager executes a paging service corresponding to the matching capcode; this pager is characterized in that any capcode or capcodes specified as being invalid are replaced with a capcode or capcodes specified as being valid based on valid/invalid flags each corresponding to respective one of the capcodes.

Abstract: In a radio receiver for electronically selecting channels by way of the frequency synthesizer system, a highspeed channel scanning operation is realized. A CPU (central processing unit) detects both an SC (squelch control) signal derived from a squelch circuit and an output voltage from a frequency discriminator. The CPU controls data to be supplied to a PLL (phase-locked loop) circuit employed in a frequency synthesizer so as to perform a channel scanning operation scanning three channels concurrently. When the CPU judges that a desirable reception signal is detected based on a change in the SC signals during the concurrent scan operation. This CPU determines at which channel, the scanning operation is stopped among three channels: the central channel of the three channels searched during the concurrent scan operation, a channel higher in frequency than this searched channel by 1 step, and a channel lower in frequency than this searched channel by 1 step.

Abstract: A cordless telephone set comprises a base unit and a handset unit connected by a radio frequency (RF) link which is established by digital burst data transmission and is synchronized by a unique word which is included in the digital burst data. The radio transmission signal is not continuous and it requires the synchronization. The unique word is detected by the unique word detecting means and is used to establish the burst data synchronization. The unite word consists of frequency channel information and fixed unite data. By using this information, the base unit and the handset unit are prevented from trying to establish a radio link at incorrect frequency when a spurious signal, not intended for the base unit and/or handset unit is erroneously received.

Abstract: A direct digital synthesizer which can be switched at a high speed and generates signals having a relatively high frequency with low power consumption; including a clock generator, a frequency setting circuit in which phase increment for unit clock can be programmed, a phase accumulator in which phase increment is accumulated, a ROM which outputs a digital signal corresponding to cumulative phase output, a D/A convertor which inverts polarity of output in each clock time, and a band-pass filter. The output of the band pass filter may be used as a reference input to a phase locked loop.

Abstract: An automatic tuning system in a high-speed scanning radio receiver provided with (a) a noise squelch circuit, first and second detecting circuits, first and second control circuits, a CPU circuit providing PLL data, and a scanning stop function. The squelch circuit generates a first (SP) signal when a decreasing trend in a noise detection voltage becomes lower than a preset reference voltage. The first detecting circuit judges whether or not the SP signal is generated within first predetermined time period (M1).

Abstract: A cordless telephone apparatus detects the received field strength in a receive channel, as viewed from the base unit side, and if the field strength is below a prescribed level outputs an out-of-range signal on a receive channel, as viewed from the base unit side. The remote unit is provided with a volatile memory area for storing channel connection state data indicating whether or not two-way radio communication was established between the remote unit and the base unit. A backup power source enables the contents of the volatile memory area to be maintained even if there is an interruption in the supply of power from the battery in the remote unit. A call resumption control circuit to resume transmission of call information from the remote unit when internal power in the remote unit is supplied from the battery.

Abstract: To avoid deterioration of isolation between two distributed power outputs in higher and lower end portions of an available frequency region of a Wilkinson power distributor, plural stages of ferrite-loaded close-coupled parallel dual lines for providing a Wilkinson power distributor, an electric length of which lines is shortened within a range in which desired isolation can be obtained, are connected in cascade. As a result, two distributed power outputs having a constant phase difference with sufficient isolation throughout an extremely wide frequency range can be obtained.

Abstract: To realize an element presenting a constant impedance throughout an extremely wide frequency range and a circuit supplying a high frequency signal having a constant phase throughout the same wide frequency range, a ferrite-loaded line element, a real part of a terminal complex impedance of which is substantially constant, is provided. A partial inclination of an imaginary part of the terminal complex impedance is compensated by providing a pure reactance element, in combination therewith As a result, in an extremely wide frequency range exceeding a natural magnetical resonant frequency, a ferrite-loaded constant impedance element and a constant phase circuit comprising this constant impedance element can be attained.

Abstract: In a dielectric material block surrounded by a metal film at least one air hole is provided. Inner faces of the at least one air hole are partly applied with at least one metal film. The at least one air hole is provided for providing coupled distributed lines, which are mutually coupled by electric fields passing partly through the at least one air hole, so as to realize a dielectric band pass filter, which has a small-sized structure and attains high precision and non-alignment of resonant frequency.

Abstract: A scanning receiver is formed of a memory for storing reception frequencies corresponding to a plurality of reception channels; a receiving section for receiving radio waves to be tuned to the reception frequencies; a control device for controlling the memory and the receiving section so as to read out the reception frequencies corresponding to the reception channels successively in a predetermined order from the memory in predetermined order to thereby cause the receiving section to operate.

Abstract: A pager has a display and a selectively activated light for illuminating the display. The illumination of the display is accomplished using a minimal number of components thereby reducing the size and cost requirements of the pager. The method of message sequencing and the illumination of the pager display is controlled solely by the pager user through a single switch.

Abstract: A portable cellular telephone having a loud speaker for implementing a monitor mode function which operates separately from the normal head set mode of operation and further has a default mode selector which varies the monitor mode function depending on whether a call is being initiated or received. The portable cellular telephone further has a display for displaying the current mode of the monitor mode function.

Abstract: A method and an apparatus for adjusting the direction of an antenna on the basis of the C/N in a satellite broadcasting receiving system are disclosed. When the image quality is insufficient with the antenna direction in a displaying mode, a user specifies a fine adjustment mode through a key input portion. Then the current antenna direction is stored into a memory as a fine adjustment start position. A CPU deflects the antenna within a predetermined measuring range around the fine adjustment start position. The CPU detects one or more peaks of the C/N level and discriminates non-objective peaks. If the C/N level exhibits a plurality of peaks resulting from the signal reception, the CPU selects the antenna direction corresponding to the peak closest to the fine adjustment start position.

Abstract: For sufficiently shielding an undesired electro-magnetic wave from penetrating into a communication apparatus, for instance, a car telephone through stray coupling, or leaks therefrom, an electronic circuit substrate and a case of the communication apparatus are formed of flat plates which consist of insulating material comprising magnetic material. One side surface of the flat plates are covered with conductive films. The communication apparatus itself is accommodated in the case and an electric power source connecting cable is wrapped by a similar arrangement, so as to remarkably reduce obstructions caused by undesired waves and other communications in comparison with the conventional arrangement.