Nippon Telegraph and Telephone Corporation

Pioneer Electronic Corporation

Akira Misawa

Masaru Katayama

Satoru Okamoto

Eiji Oki

Tatsuo Numata

Naoaki Yamanaka

Masahiro Nakagawa

Kyota Hattori

Naoki Kimishima

An optical network system includes a master node and a plurality of optical switch nodes, allowing the number of nodes without depending on the number of wavelengths. The master node is configured to: divide a wavelength path having an arbitrary wavelength into time slots each having a predetermined time period; and allocate the time slots to each of the optical switch nodes. Each of the optical switch nodes is configured to: synchronize the time slots based on information delivered from the master node; and thereby transmit or receive a data or performs route switching.

Optical network system, optical switch node, master node, and node

An economical optical network is constituted by effectively using network resources by using the minimum number of, or minimum capacity of 3R repeaters. 3R section information corresponding to topology information on the optical network to which an optical node device itself belongs is stored, and the 3R section information stored is referred so as to autonomously determine whether or not the optical node device itself is an optical node device for implementing the 3R relay when setting an optical path passing through the optical node device itself. Alternatively, when the optical node device itself is a source node, another optical node device for implementing the 3R relay among the other optical node devices through which the optical path from the optical node device itself to the destination node passes is identified, and this identified optical node device is requested to implement the 3R relay when setting an optical path in which the optical node device itself is a source node.

Optical node device, network control device, maintenance-staff device, optical network, and 3R relay implementation node decision method

An OVPN user register an L1 signal type information which is used in the user's device in an OVPN terminating device in advance together with an IP address and a VPNID which are allocated to the user's device. Registered contents are notified to other OVPN terminating devices which control the same VPNID as that of the user's device. Otherwise, when a calling connection request arrives from the user's device, the registered contents are notified other OVPN terminating devices which control the devices which receive the notification. By doing this, it is possible to handle a request by the user for changing the setting for the signal format which is employed in the user's device quickly. Also, it is possible to realize an OVPN which can perform a process for a calling connection request from the user efficiently and improve an operability for the user.

OVPN system, OVPN terminating device, collective controlling device, and optical communication network

A product or multiplier circuit for use in an FM quadrature detector including a double-balanced differential amplifier having resistors disposed in the emitter circuits thereof. Product signals formed at collector junctions of the differential amplifier are amplified by a differential amplifier transistor pair having its emitter circuits fed by a current source and its collector circuits coupled to a current mirror circuit. By restricting the resistance values of the emitter circuit resistors of the double-balanced differential amplifier within a disclosed range, the distortion factor and signal-to-noise ratio of the circuit are improved.

Product circuit

A PLL tuning device in a receiver uses a digital memory board and array of photo-transistors scanning the memory board for station selection. When the transistors are lined up with a column, a digital output is fed to a switching device and to a programmable frequency divider. Muting action is released when the output is delivered to the divider, but, when the array is between columns, muting action takes place. In one embodiment, the photo-transistor output is fed to a latch and to an OR gate serving as the switch. A one-shot is triggered in response to the setting of the OR gate at an H level. Digital information is fed to the programmable frequency divider from the latch until the one-shot is fired. In another embodiment, the latch and one-shot are eliminated. Photo-transistor output is fed to both an OR gate and the frequency divider. The OR gate controls a switch that closes muting switches only when information is being generated by the photo-transistors. However, when the sensor array is between signals the tuner is maintained in a muted state.

Tuner with phase locked loop synthesizer

A digital tuning FM stereophonic receiver of the type including a phase locked loop synthesizer. A digital code generating circuit is provided for generating a digital code which consists of several bits to be applied to a programmable frequency divider inserted in the phase locked loop. At least one auxiliary bit is provided together with the bits of the digital code. The information of the auxiliary bit is used to input and hold the digital code to be applied thereto. Muting operation of the FM stereophonic receiver is controlled in accordance with the information of the auxiliary bit.

Digital tuning FM stereophonic receiver including phase locked loop

A tuning indicating device in a radio tuner displays S-meter and T-meter tuning information in a single, two-dimensional display. The display unit forms a two-dimensional pattern in response to drive signals corresponding to the S-meter and T-meter tuning information and preferably comprises two groups of electrodes disposed to sandwich a plate-shaped member made of a material whose optical characteristic is changed in response to an electrical field strength applied thereto. One of the groups of electrodes is a plurality of film electrodes which are aligned in one and the same direction, while the other is a plurality of film electrodes which are arranged in such a manner that the configurations thereof are different from one another gradually in a predetermined direction and which are aligned in a direction different from the direction of the one group of film electrodes.

Growing community of inventors

Tokyo, Japan

Akira Misawa