In a keyboard electronic musical instrument having tone generators of frequency divider systems, every key is associated with and controls a plurality of tone keyers which respectively gate tone signals having frequencies being harmonically related with each other. The tone signal gated by one of the keyers is passed through a frequency shifter, while the tone signal gated by the rest of the keyers is not. Among the tone keyers, the above-mentioned one is a keyer for producing an attack signal, while the remainder are keyers for producing a normal lasting signal. Both signals, now being slightly out of harmonic relation, are mixed together and finally transduced into sound by a loudspeaker. The produced sound has subtly fine musical results with a sense of many different tone sources as in an individual--oscillator system instrument.

Electronic musical instrument

An integrated LED driving device for multiple LED strings which employs a single linear regulator or other controller and a multiple-output current mirror which is almost independent of the DC input voltage source, almost independent of the transistor's or MOSFET's variations from the semiconductor integration process, and almost independent of temperature variation The multiple-output current mirror includes a plurality of transistors or MOSFETs each of which are integrated on the same substrate, with identical width-to-length channel ratios and with identical source and gate connections The integrated LED driving device provides for automatic current sharing in a DC mode and, alternately, with minimized phase delays in a PWM mode The mirror-output current mirror may include mirror-cascode transistor pairs

Integrated LED driving device with current sharing for multiple LED strings

In a module socket, a connecter and a connector are connected by wiring, and three LED modules are connected in parallel with respect to a constant voltage circuit unit via the wiring. Each module has a constant current circuit unit and an LED mounting unit. The constant current circuit unit includes one resistor and two transistors mounted on a surface of a sub-substrate on which a conductive land is formed. The sub-substrate is bonded to a main substrate.

Multichip led lighting device

An amplifier is disclosed including at least three integrator stages connected to provide a low-frequency path from a signal input to a signal output, and a relatively high-frequency bypass path around the first integrator stage. The first integrator stage uses dynamic offset reduction such as chopper stabilization, and an analog low-pass filter reduces artifacts of the dynamic offset reduction. The paths converge at a current summing node. To prevent instability when the integrators are saturated by large signals, the paths have respective saturation current limits selected so that the relatively high-frequency path is not saturated when the low-frequency path saturates. To ensure that the conditional stability is substantially unaffected by adjustment of closed-loop gain, a current feedback input adjusts the open-loop gain in a fashion inversely proportional to resistance presented to the current feedback input by a feedback circuit.

High-order multipath operational amplifier with dynamic offset reduction, controlled saturation current limiting, and current feedback for enhanced conditional stability

A switched capacitor N-path filter in which all capacitors that introduce delay in the paths, in that they have memory and are characterized such that the new charge flow into each such capacitor during each commutation cycle depends on the old charge on it from the previous commutation cycle, are replaced with an associated plurality of N-commutating capacitors.

Switched capacitor n-path filter

A switched capacitor filter having at its input, a signal converter for creating so-called 100% sample and hold signals. The signal converter comprises a plurality of switched capacitors. The switched capacitors, connected in parallel with each other, receive the same successive input signals and supply the so-called 100% sample and hold input signals to the switched-capacitor filter. The switched capacitors, on one hand, charge each of said input signals sequentially and, on the other hand, alternately discharge the respective stored input signals one by one.

Switched-capacitor filter

A digital adaptive equalizer equalizes received signals through digital filtering operations by changing filtering coefficients. It comprises a coefficient calculating unit for calculating the filtering coefficients by using one kind of parameters, such as distance, as an input to a function corresponding to the filtering coefficients and a filtering operation executing unit for executing digital filtering operations based on the filtering coefficients. A variable lag filter for adjusting the phase delay of received received signals is provided. A coefficient converting unit calculates a part or all of tap coefficients of the filter using at least one piece of timing control information.

Received data adjusting device

We propose a novel cell-AGC technique for an ATM-cell based burst optical receiver on a 156 Mbps subscriber system. The cell-AGC controls transimpedance gain according to the burst cell power and enables reception of burst signals with low extinction ratio. In addition, to realize high sensitivity, we developed an amplifier that is stable under changes in ambient conditions and deviations of transistor characteristics on IC. By adopting these techniques in a CMOS preamplifier-IC, the detectable power difference between burst cells was enlarged to more than 30 dB, and the minimum sensitivity was improved to less than -39.3 dBm. These performances show our new IC fully satisfy high sensitivity specification of an ATM-PON system, and incorporating this IC in the system makes it more flexible and economical.

Novel cell-AGC technique for burst-mode CMOS preamplifier with wide dynamic range and high sensitivity for ATM-PON system

We propose a novel cell-AGC technique for an ATM-cell-based burst optical receiver on a 156-Mb/s subscriber system. The cell-AGC controls transimpedance gain according to the burst-cell power and enables reception of burst signals with low extinction ratio. In addition, to realize high sensitivity, we developed an amplifier that is stable under changes in ambient conditions and deviations of transistor characteristics on IC. By adopting these techniques in a CMOS preamplifier IC, the detectable power difference between burst cells was enlarged to more than 30 dB, and the minimum sensitivity was improved to less than -39.3 dBm. These performances show that our new IC fully satisfies the high-sensitivity specification of an ATM-PON system, and incorporating this IC in the system makes it more flexible and economical.

An integrator for use in a switched capacitor-filter, in which switching elements are connected to an input and to an output of an operational amplifier included in the integrator for clamping the input and output to a ground potential during suspension of the integral operation, in order to prevent potentials at the input and output of the operational amplifier from varying and hence ensure rapid stabilization of the integral operation of the integrator.

Norio Ueno

Papers

Switched-capacitor filter

Received data adjusting device

Novel cell-AGC technique for burst-mode CMOS preamplifier with wide dynamic range and high sensitivity for ATM-PON system

Novel cell-AGC technique for burst-mode CMOS preamplifier with wide dynamic range and high sensitivity for ATM-PON system

Integrator for a switched capacitor-filter