摘要:
A motor driver system and its control methods are discussed. Even when a command magnetic flux decreases as a motor operates in a field weakening region, a current angle can be maintained always below a limit value, thereby obtaining the stability of the motor control.
摘要:
A motor driver system includes an excess current sensing device configured to compensate a sensing value depending on a temperature of a motor, and to output the compensated sensing value, the sensing value being obtained from a current value associated with the motor; and a controller configured to stop the motor when the compensated sensing value exceeds a preset excess value.
摘要:
A motor driver system includes an inverter configured to apply a three-phase voltage to a motor; an inverter driver configured to generate a reference voltage to the inverter to control a motor speed to follow a reference speed; and a motor protector configured to control the inverter driver so that a value of the reference voltage is equal to or lower than a predetermined voltage value.
摘要:
Provided are a method and apparatus for partially encrypting speech packets, more specifically, a method and apparatus for selecting partial encryption sets used for a partial encryption technique in which compressed speech packets are partially encrypted to obtain the same effect as a full encryption technique. The method includes the steps of: (a) compressing respective speech files stored in a large-capacity speech database into the speech packets using a speech codec; (b) measuring single-bit loss distortion and sequential-bit loss distortion of the speech packets compressed in step (a); (c) generating standards for selecting partial encryption sets based on the measurement results of the single-bit loss distortion and sequential-bit loss distortion; (d) selecting the partial encryption sets according to the generated standards; and (e) encrypting the speech packets using the selected partial encryption sets. In this method, distortion sensitivity caused by loss of a speech packet can be exactly measured in various embodiments so that partial encryption sets can be efficiently and securely selected based on the measurement result. As a result, by reducing the amount of encryption operation, encryption services can be applied in various wireless communication environments.
摘要:
Disclosed is an organic electroluminescent device including a substrate, a first and a second electrode, and an emitting layer formed between the first electrode and the second electrode. The emitting layer includes a plurality of materials which is a blue emitting material using a following chemical formula as dopant. In this case, at least one of A1 and A2 is selected from a substituted or non-substituted aromatic group, a heterocyclic group, an aliphatic group, and hydrogen.
摘要:
A sample-and-hold circuit connected to an analog-to-digital converter (ADC) is provided. The sample-and-hold circuit includes an operational amplifier configured to output a result signal to the ADC; a feedback capacitor connected between an input terminal and an output terminal of the operational amplifier to form a feedback path; a plurality of sampling capacitor blocks each connected to one of a plurality of channels. The plurality of sampling capacitor blocks configured to sample and hold an analog signal input to each of the channels; a plurality of controllers each connected between one of the sampling capacitor blocks and the operational amplifier. The plurality of controllers configured to switch the sampled signal so that held signals for the respective channels are sequentially input to the operational amplifier; and a reset unit connected between a reference voltage source and the input terminal of the operational amplifier to reset the operational amplifier when the operational amplifier does not perform a holding operation.
摘要:
An organic electroluminescent (EL) device is provided that may include a first electrode, an organic layer and a second electrode arranged in a light-emitting region of a substrate. The device may also include a cap for sealing the light-emitting region of the substrate. The cap may have a caved surface with a minimum depth of 10 μm and a maximum depth of 10% of a total thickness of the cap.
摘要:
An electron transporting-injection compound, represented by following Formula 1: wherein each of the R1, the R2 and the R3 is selected from substituted or non-substituted aromatic group, substituted or non-substituted heterocyclic group, or of substituted or non-substituted aliphatic group, and at least one of the R2 and the R3 is selected from substituted or non-substituted heterocyclic group.
摘要:
Provided are a device and method for detecting a wiretapping device using a power line and nullifying the wiretapping device. More particularly, a device and method for preventing wiretapping, which sense a wiretapping signal from a power line and transmit a noise signal to the power line, are provided. The device for preventing wiretapping includes: a signal detector for receiving signals from a power line and filtering the received signals in at least one frequency band; a controller for receiving the filtered signal from the signal detector and determining whether a wiretapping signal exists; and a noise signal output unit for transmitting a noise signal to the power line according to whether or not the wiretapping signal exists. The device can detect wiretapping and simultaneously nullify the function of the wiretapping device by detecting a wiretapping signal from a power line and transmitting a noise signal having a frequency corresponding to a frequency band of the wiretapping signal.