Abstract: In order to compensate for chromatic dispersion caused by optical fiber transmission in a communication system with coherent detection using optical signals, specific frequency band signals are used to enable estimation of a chromatic dispersion value.

Abstract: To enable signal position detection, frequency offset compensation, clock offset compensation, and chromatic dispersion amount estimation in a communication system based on coherent detection using an optical signal, even on a signal having a great offset in an arrival time depending on a frequency due to chromatic dispersion. An optical signal transmitting apparatus generates specific frequency band signals having power concentrated on two or more specific frequencies and transmits a signal including the specific frequency band signals. An optical signal receiving apparatus converts a received signal into a digital signal, detects positions of the specific frequency band signals from the converted digital signal, estimates frequency positions of the detected specific frequency band signals, and detects a frequency offset between an optical signal receiving apparatus and an optical signal transmitting apparatus.

Abstract: The present invention provides an inexpensive small-sized liquid level detector. A liquid level detector 1 includes a float moving in accordance with variations in liquid level, a hard circuit board 5, resistors 12a and 12b provided on the circuit board 5, a first sliding path 14 made of a plurality of electrodes 13 provided on the circuit board 5 and connected to the resistors 12a and 12b, and a first contact 6 coming into contact with the first sliding path 14, and the liquid level detector 1 outputs an electrical signal based on the resistances of the resistors 12a and 12b which are varied by the first contact 6 coming into contact with at least one of the plurality of electrodes 13 forming the first sliding path 14 in accordance with a variation of the float.

Abstract: The present invention provides an inexpensive small-sized liquid level detector. A liquid level detector 1 includes a float moving in accordance with variations in liquid level, a hard circuit board 5, resistors 12a and 12b provided on the circuit board 5, a first sliding path 14 made of a plurality of electrodes 13 provided on the circuit board 5 and connected to the resistors 12a and 12b, and a first contact 6 coming into contact with the first sliding path 14, and the liquid level detector 1 outputs an electrical signal based on the resistances of the resistors 12a and 12b which are varied by the first contact 6 coming into contact with at least one of the plurality of electrodes 13 forming the first sliding path 14 in accordance with a variation of the float.

Abstract: A liquid level detecting apparatus 1 having detachable terminals and capable of holding down the formation of silver sulfide is provided. The apparatus includes a movable contact 2 displaced in accordance with the fluctuation of a liquid level, a slide 5 slidingly moved at the movable contact 2 on a circuit board 4, a resistance 7 connected to the slide 5, and connecting portions 8 which the terminals 9 contact, a resistance value of the resistance 7 which varies when the movable contact 2 is slidingly moved on the slide 5 being outputted from the terminals 9 via the connecting portions 8, wherein the sections of the connecting portions 8 which contact at least the terminals 9 are covered with second resistances 16.

Abstract: A liquid level detecting apparatus resistant to the deterioration and corrosion thereof is provided while holding down an increase in the manufacturing cost thereof. This apparatus 1 has fixed electrodes 3 on which a sliding contact point 5 is slidingly moved in accordance with a fluctuation of a float, and a first resistor 4 connected to the fixed electrodes 3, the fixed electrodes 3 being made of at least silver (Ag), palladium (Pd) and a glass component, a weight ratio of the silver (Ag) to palladium (Pd) being not lower than 75 wt. % to not higher than 25 wt. %, a sliding portion 7 of the fixed electrodes 3 on which the sliding contact point 5 is slidingly moved being covered with second resistors 8 a resistance value of which is lower than that of the first resistor 4.

Abstract: A liquid level detecting apparatus resistant to the deterioration and corrosion thereof is provided while holding down an increase in the manufacturing cost thereof. This apparatus 1 has fixed electrodes 3 on which a sliding contact point 5 is slidingly moved in accordance with a fluctuation of a float, and a first resistor 4 connected to the fixed electrodes 3, the fixed electrodes 3 being made of at least silver (Ag), palladium (Pd) and a glass component, a weight ratio of the silver (Ag) to palladium (Pd) being not lower than 75 wt. % to not higher than 25 wt. %, a sliding portion 7 of the fixed electrodes 3 on which the sliding contact point 5 is slidingly moved being covered with second resistors 8 a resistance value of which is lower than that of the first resistor 4.

Abstract: A direct digital synthesizer capable of generating a desired frequency with small circuitry, low power consumption, and no spurious components. It includes an accumulator for accumulating a frequency control word for each pulse of a clock signal, a D/A converter for converting the accumulation value of the accumulator to an analog voltage, an integrator for smoothing the output of the D/A converter, a comparator for comparing the output of the integrator with a reference voltage, and for producing pulses at timings at which the output of the integrator reaches the reference voltage while the accumulation value of the accumulator is increasing, and a pulse generator for producing pulses in synchronism with the rising edges of the output of the comparator. The output pulses of the pulse generator constitute an output of the direct digital synthesizer.

Abstract: A fractional-N frequency divider system generates an output signal having frequency of an input signal divided by a desired frequency division ratio (N+A/M) in which N is an integer and A/M is a fraction, A.ltoreq.M, and includes a programmable frequency divider receiving input frequency and providing divided frequency in which division ratio (N, N+1) is an integer and is externally supplied, a selector supplying one of the externally supplied integers (N, N+1) to the divider according to a selection signal, and a fractional part set having a first counter initialized to count M, a second counter initialized to count A, and a logic circuit for supplying the selection signal according to the counters. The counters are decremented by an output of the divider and reach zero when they receive M and A number of pulses, respectively. The second counter stops counting operation when it reaches zero.

Abstract: A device comprising two oil reservoir tanks communicating with the two respective oil-hydraulic chambers of a tandem type master cylinder and also with each other through an upper and a lower interconnecting oil passage. One of the two tanks has a top opening for oil filling use and normally closed with a vented cap while the other tank is closed at the top and provided therein with an oil level detector means which comprises a stationary reed switch connected with an appropriate external alarm circuit and a permanent magnet vertically movable with the oil level in the tank to close the reed switch as the volume of oil stored is reduced to a predetermined minimum. With the device, even if one of the two oil-hydraulic lines connected with the master cylinder fails to function due to oil leakage, the other line can properly function without any pressure failure as, in the associated tank, a predetermined minimum volume of oil remains on account of the height of the lower oil passage.

Abstract: A disc brake device for motor-cycles and the like, constructed with a fixing bracket of inverted U-shape, having a flat horizontal roof plate and downwardly extending side plates, a pair of caliper arms joined together by a connecting rod and slidably mounted thereon in the space provided between the side plates, a fixed friction brake pad held in one of the caliper arms, a movable friction brake pad slidably inserted in a bore formed in the other caliper arm so as to be clamped with a brake disc of a wheel of the vehicle, interposed between the friction brake pads by a brake actuating lever through a screwing action between a male threaded nut member and a female threaded screw member embedded in the caliper arm that accommodates the movable friction pad, and an adjustment bolt provided concentrically with the screw and nut members to compensate wear occurring in the movable friction pad, the brake actuating lever being fitted to a square shaft provided at the end of the screw member, and tightly fastened th

Abstract: A fluid level alarm device which is capable of warning a person of a shortage in level of an operating fluid stored in a fluid tank and in which the critical fluid level at which an alarm signal is produced is determined with a maximized accuracy by positioning a magnetically operable reed switch, electrically connected to an alarm, within the tank at a predetermined vertical location in a manner so that, when the fluid stored in the tank is lowered below a specified level, said reed switch is magnetically closed to operate the alarm.

Abstract: An oil-hydraulic servo-motor, usable with an automotive brake, including a control piston slidably extending through the rear end wall of a power cylinder in aligned opposite relation to an output piston therein and forming together with the cylinder end wall a spool-type control valve which is operable to energize and de-energize the power cylinder. The control piston is axially movable normally within definite limits under the operator's input, and abutment means provided to limit the extent of advancing movement of the control piston is rendered inoperable automatically upon failure of an associated oil pressure circuitry to enable the control piston to drive the output piston directly under the operator's input. The oil pressure circuitry may be formed in two independently operable systems. Major features include simplicity of the valving mechansim and hence of the entire structure of the servo-motor and a highly improved reliability in operation.