Abstract: A fan system includes a motor control module external to a motor housing of a fan assembly. The motor control module includes a speed control module. The fan assembly includes a fan and the motor housing. One or more first conductors are configured to connect the motor control module to a motor in the motor housing. One or more second conductors are configured to connect the motor control module to a host device control module. The host device control module is separate from the motor control module and is configured to generate a control signal. The speed control module is configured to control speed of the fan based on the control signal.

Abstract: A fan control system includes a linear adjustor, an input/output controller, and a temperature sensor. A first terminal of the linear adjustor is connected to a first power supply. A second terminal of the linear adjustor is connected to a fan and grounded via a first resistor and a second resistor in series. A third terminal of the linear adjustor is connected to a node between the first resistor and the second resistor. A first terminal of the input/output controller is connected to the third terminal of the linear adjustor via a third resistor. A second terminal of the input/output controller is connected to the temperature sensor.

Abstract: A computer-based method for adjusting pulse width modulation (PWM) signals according to temperatures of one or more computer components includes setting a frequency formula for a fan in a computer. The method further includes reading current temperatures of one or more components in the computer from a temperature measuring device. Furthermore, the method includes computing a frequency according to the frequency formula and the current temperatures, and sending the computed frequency to a PWM signal manager for generating an adjustment PWM signal to control the rotational speed of the fan in the computer.

Abstract: In a rechargeable electric power tool, upon changeover of a trigger switch, a microcomputer determines the magnitude relation between the detected temperature outputted from the first thermistor and the first temperature threshold value, the second temperature threshold value and the third temperature threshold value, and the magnitude relation between the first calculated temperature increase rate and the first preset temperature increase rate. If the detected temperature is determined to be greater than the first temperature threshold value or if the first calculated temperature increase rate is determined to be greater than the first preset temperature increase rate after the detected temperature has been determined to be greater than the second temperature threshold value, the microcomputer is set in a limited operation mode in which the revolution number of the motor is limited to a predetermined value or less.

Abstract: A method for testing an electric motor which is connected to a valve element by at least one component comprises starting the motor, measuring a movement parameter of at least one of the motor and the component without moving the valve element, and stopping the motor when the measured movement parameter indicates that the valve element is about to move.

Abstract: A fire or smoke barrier 1 has a curtain 2 deployed from a motorized roller 3 mounted in a head box 4. Remote from the head box and connected to the motor via a cable 5 is a motor controller circuit 6. A short circuit protection circuit 9 is connected to the motor within the roller at the motor end of the cable 5. On the motor side of the circuit 9 is a retarder circuit 10 connected across the motor terminals. The short circuit circuit comprises a pair of relays 11, 12, arranged with their normally open contacts 111,121 arranged in parallel. A drive voltage one 11 of the relays has its winding 112 across the input lines 14 of the circuit and the emf one 12 of the relays has its winding 122 across the output lines 15 of the circuit. The input lines 14 are connected to the cable lines 51,52 and the output lines 15 are connected to the motor terminals 16, via the retarder 10.

Abstract: A method of controlling a washing machine and a motor determines whether a BLDC motor is in a normal state in software without hardware and a user is notified of an abnormal state of the BLDC motor if the BLDC motor is in an abnormal state, thereby ensuring safety. When the motor is rotated, the state of the motor is determined by applying harmonics to a voltage that is applied to a motor and analyzing an output frequency characteristic. When the motor is stopped, the state of the motor is determined by estimating the temperature of the motor.

Abstract: A first calculation unit subtracts third digital data which indicates the minimum value of the duty ratio from first digital data which indicates the duty ratio of the PWM driving operation. A slope calculation unit generates slope data which is dependent on the temperature based upon second digital data which indicates the temperature. A second calculation unit multiplies the slope data by the output data of the first calculation unit. A third calculation unit sums the output data of the second calculation unit and the third digital data. A selector receives the output data of the third calculation unit and the third digital data, selects one data that corresponds to the sign of the output data of the first calculation unit, and outputs the data thus selected as a duty ratio control signal.

Abstract: An electrically-driven dump truck 1 uses resistors to convert electric power generated during retarder braking operation into heat energy. A body frame 2 has front and rear wheels, a support base 2A, a cab 4 mounted on an upper left surface of the support base, and a control cabinet 3 mounted on an upper surface of the support base. A plurality of resistor boxes 5 are mounted on an upper base plate 2B and are arranged in a stacked manner such that the plurality of resistor boxes 5 are located to the right of the control cabinet 3 in order to secure right side visibility from the cab 4. Each resistor box has a casing with plural resistors connected in parallel, an inlet port and an outlet port. A fan for cooling the resistors is housed in the casing.

Abstract: A fan duty cycle controlling system and method are implemented by a computing device. The fan duty cycle controlling system obtains an optimum duty cycle range of a fan around a central processing unit (CPU), and controls the fan to operate at the optimum duty cycle range. By implementing the system and method, the computing device can obtain an optimum cooling efficiency of the computer system, and reduce system noise generated by the fan when the fan operates at the optimum duty cycle range.

Abstract: The apparatus for controlling an inverter is disclosed which detects a rotation angle of a load using a current supplied to the load when the inverter utilizes a voltage/frequency control to control the driving of the load, and accurately drives the load using the detected rotation angle, where the current supplied to the load by the inverter is detected by a current sensor, and a rotation speed of the load is estimated by the detected current to be used for the driving of the load.

Abstract: A fan control system includes a temperature detecting circuit and a rotation rate control circuit. The detecting circuit includes an amplifier and a thermal diode. The detecting circuit detects temperature and outputs a voltage signal. The control circuit receives the voltage signal and controls the rotation rate of the fan according to the voltage signal.

Abstract: An electrical power supply unit for vehicle comprises: a Main Power Supply 100, a Voltage Converter 40 for converting the output voltage of the Main Power Supply 100 to supply electrical power to a Motor Drive Circuit 30, a Subsidiary Power Supply 50 to be charged by the Voltage Converter 40 and to aid the electrical power supply for the Motor Drive Circuit 30 with its stored electrical power, and an Electrical Power Supply Control Unit 62 to control the converted voltage of the Voltage Converter 40. The Electrical Power Supply Control Unit 62 controls the converted voltage of the Voltage Converter 40 based on the Voltage Converter Temperature Tb and the Subsidiary Power Supply Temperature Ts so that the heat generation condition of the Voltage Converter 40 and the heat generation condition of the Subsidiary Power Supply 50 are balanced.

Abstract: A cooling system is provided with a motor drive device, a fan motor, and a Hall element. The motor drive device includes a lock protection circuit and a lock controller. When a control signal instructing rotation of the fan motor that is to be driven instructs stoppage of the motor for a predetermined time-period or longer, the lock controller has the lock protection circuit inactive. At an occasion when the control signal has continued to instruct stoppage of the fan motor for a first time-period or longer, a standby controller starts time measurement, and after a further predetermined second time-period has elapsed, makes at least a part of the motor drive device transition to a standby mode.

Abstract: A fan control system includes a temperature detecting circuit and a rotation rate control circuit. The detecting circuit includes a first amplifier, a second amplifier, and a thermistor. The control circuit includes a first terminal, a second terminal, and a third terminal. The detecting circuit detects temperature and outputs a voltage signal. The control circuit receives the voltage signal and controls the rotation rate of the fan according to the voltage signal.

Abstract: Provided is an electric compressor whose manufacturing cost is reduced and in which a motor driving circuit can be positively protected. A temperature sensor is provided in the vicinity of a power semiconductor element whose temperature becomes highest among a plurality of power semiconductor elements and control of the number of revolutions of a motor is performed on the basis of temperatures detected by the temperature sensor, whereby it is possible to change the number of revolutions of the motor by using a temperature in the vicinity of a power semiconductor element in a position under the worst temperature conditions as a reference, and it becomes possible to positively protect an inverter circuit without the need for a plurality of temperature sensors.

Abstract: A fan delay controlling apparatus includes a connector connected to a fan of an electronic device, a power supplying module connected to the connector, and a power controlling module connected to the power supplying module. The power supplying module is connected to a fan power source and a stand-by power source. The power controlling module controls the power supplying module supply power to the fan when the electronic device including the fan powers off until an ambient temperature is lower than a predetermined value.

Abstract: An aircraft engine starting system may comprise a starter motor, a start controller for controlling the starter motor to operate with a desired torque output, and a processor for determining torque profiles for the starter motor. The processor may provide an initial torque profile responsively to ambient condition of the engine. The processor may also provide modifications to the initial torque profile responsively to temperature of the start controller.

Abstract: When the fan inserted in the fan header is a 4-pin fan, the control chip outputs PWM signals with different duty factors to the control pin of the fan header, to automatically change the rotary speed of the 4-pin fan. When the fan inserted in the fan header is a 3-pin fan, the control chip outputs the PWM signals whose duty factor changes with temperature of a chip under the fan to control the first power source to provide a voltage to the adjusting circuit. The adjusting circuit rectifies the voltage output from the first power source as an analog voltage signal to the control circuit. The control circuit controls the third power source to output a changeable driving voltage to the power pin of the fan header to control the rotary speed of the 3-pin fan.

Abstract: At least one embodiment of the invention relates to a protective circuit for protection of an appliance, in particular of an electric motor, against thermal overloading. In at least one embodiment, the protective circuit includes a first and a second terminal for connecting a temperature detection element; a detection unit for detecting whether a resistance value of the temperature detector element which is connected between the first and the second terminals, is in a first or a second resistance range; a short-circuit detector for identifying whether there is a short circuit between the first and the second terminals; signaling outputs for emitting signal messages to an evaluation unit when the detected resistance value is in the second resistance range and/or when a short circuit has been identified by the short-circuit detector; and a third terminal, which is connected to the second terminal via a predetermined resistance.

Abstract: A control device for controlling a recovery from a locking of a motor includes: a switching unit which supplies a motor current from a current supplying unit to the motor; and a driving control unit which supplies a PWM control signal to the switching unit to control a driving of the switching unit. The driving control unit supplies the PWM control signal with a low duty ratio lower than a regular duty ratio to the switching unit when the locking of the motor is detected depending on a variation in temperature of the switching unit. The driving control unit supplies the PWM control signal with the regular duty ratio to the switching unit when a cancel of the locking of the motor is detected depending on a variation in inter-terminal voltage of the motor.

Abstract: A torque limit section that applies limit to a torque instruction value of an electric motor such that a switching elements temperature is restricted to no more than an element upper limiting temperature includes a torque restriction section that finds a torque restriction value for restricting the torque of the electric motor in accordance with the said switching elements temperature; a torque restriction mitigation section that finds a torque restriction mitigation value for mitigating the torque limit value in accordance with the integrated value of the deviation of the element upper limiting temperature and the switching elements temperature; a first subtractor that finds a torque restriction value by subtracting the torque restriction mitigation value from the torque limit value; and a second subtractor that finds a limited torque instruction value obtained by subtracting the torque limit value from the torque instruction value and outputs this to the gate generating section.

Abstract: A method for controlling a fan speed is disclosed. The fan cools a CPU in a computer. The method includes defining a CPU-max-temp value of a CPU, such that the first fan speed is linearly enhanced with the increase of a real temperature value of the CPU, when the real temperature value of the CPU is lower than the CPU-max-temp value, and changing the CPU-max-temp value to a higher CPU-max-temp value in a basic input output system. A second fan speed is linearly enhanced with an increase of the real temperature value, when the real temperature value is lower than the higher CPU-max-temp value. The second fan speed is less than the first fan speed at the real temperature value.

Abstract: Methods and apparatus are provided for dynamic voltage control of electric motors. An inverter provides an output voltage to an electric motor based on a gate voltage. The method includes determining a speed of the electric motor and modifying the gate voltage based on the speed of the electric motor. The apparatus includes a gate drive circuit and a controller coupled to the gate drive circuit. The gate drive circuit provides a gate voltage to a switch network, and the switch network produces the output voltage in response to the gate voltage. The controller modifies the gate voltage based on a speed of the electric motor.

Abstract: Inverters of a hybrid electric vehicle are cooled by a coolant. Expected temperature differences between the inverters and the coolant are determined based on vehicle parameters. Actual temperature differences between the inverters and the coolant are compared to the expected temperature differences. A maximum output torque is reduced if the actual temperature differences exceed the expected temperature differences.

Abstract: Automated control is provided of rotational velocity of an air-moving device cooling an electronics subsystem of an electronics rack. The automated control includes: automatically responding to a failure event associated with the electronics subsystem of the rack by setting rotational velocity of the air-moving device to a first upper limit (RPM1) above a normal operating limit; sensing motor temperature of a motor of the air-moving device; automatically increasing rotational velocity of the air-moving device to a second upper limit (RPM2) if the sensed motor temperature is below a first predefined temperature threshold (T1), wherein RPM2>RPM 1; maintaining rotational velocity of the air-moving device at the second upper limit while the sensed motor temperature is below a second predefined temperature threshold (T2), wherein T2>T1; and returning to normal operating rotational velocity of the air-moving device subsequent to servicing of the electronics rack responsive to the event.

Abstract: The present invention provides an apparatus and a method for accurately detecting abnormal conditions of a motor. A ?Tc/Tj detector detects a difference (?Tc) between an environment temperature and a temperature of a field-effect transistor (FET) which turns on and off electric power supplied to a DC motor. A diagnosis control unit detects abnormal conditions such as a motor lock and a short circuit of the DC motor based upon the obtained difference. When the motor lock has been detected, the diagnosis control unit controls a pulse width modulation (PWM) control unit and a PWM oscillator (PWMOSC) and makes a frequency and duty cycle of a PWM signal lower. When the short circuit has been detected, the diagnosis control unit controls a gate driver and turns off the FET.

Abstract: Methods and apparatus are provided for operation of a voltage source inverter. A method of operating a voltage source inverter having an output with multiple voltage phases having a DC voltage level, the method comprising sensing a low output frequency condition; determining a DC voltage offset responsive to the low output frequency condition; and applying the DC voltage offset when operating the voltage source inverter resulting in a change to the DC voltage level of the multiple voltage phases.

Abstract: A fan controller includes an input module and an output module. The input module is used for receiving a power supply signal from a power supply which is used for providing power to a fan, and outputting a trigger signal when the power supply signal when the power supply turns off. The output module is used for providing power for the fan when the power supply turns off. The output module includes a timer circuit and an integrator circuit. The timer circuit is coupled to the input module, and is used for receiving the trigger signal, and providing the power for the fan according to the trigger signal for a predetermined amount of time. The integrator circuit is used for providing a threshold voltage for the timer circuit, the threshold voltage tripping termination of the power provided by the timer circuit.

Abstract: A rechargeable electric power tool includes a motor driven by a secondary battery, a switching element for regulating power distribution to the motor, a motor control unit for controlling rotation of the motor through the switching element, a lead wire for supplying a drive current to the motor therethrough and a trigger switch changed over by a user for turning on or off the drive current supplied to the motor through the lead wire. In the rechargeable electric power tool, upon changeover of the trigger switch, a microcomputer determines a magnitude relation between a detected temperature outputted from a first thermistor and a first temperature threshold value. If the detected temperature is determined to be greater than the first temperature threshold value, the microcomputer is set in a limited operation mode in which a revolution number of the motor is limited to a predetermined value or less.

Abstract: In a rechargeable electric power tool, upon changeover of a trigger switch, a microcomputer determines the magnitude relation between the detected temperature outputted from the first thermistor and the first temperature threshold value, the second temperature threshold value and the third temperature threshold value, and the magnitude relation between the first calculated temperature increase rate and the first preset temperature increase rate. If the detected temperature is determined to be greater than the first temperature threshold value or if the first calculated temperature increase rate is determined to be greater than the first preset temperature increase rate after the detected temperature has been determined to be greater than the second temperature threshold value, the microcomputer is set in a limited operation mode in which the revolution number of the motor is limited to a predetermined value or less.

Abstract: A cooling system for a retarding system of an electric drive machine (100) includes a direct current (DC) link having first and second rails. A first resistor grid (214) is selectively placed in circuit between the rails by an automatic switch (216) in response to a switch (216) signal. A second resistor grid (218) is selectively placed in circuit between the rails by a chopper circuit (220) connected in series with the second resistor grid (218). The chopper modulates a current passing therethrough based on a duty cycle. A motor (336) is in parallel electrical connection across a portion of the first resistor grid (214) and operates in response to a motor (336) signal. An electronic controller (400) calculates a net energy during operation and adjusts the switch (216) signal, the duty cycle, and the motor (336) signal to close the automatic electrical switch (216) and operate the motor (336) when the net energy exceeds a threshold value.

Abstract: There is provided a control device of a permanent-magnet type synchronous motor that sets a synchronous operation current at start-up in response to a current limiting value determined from the temperature of an inverter that supplies three-phase power to the permanent-magnet type synchronous motor, that monitors an output voltage or an output current of the inverter during a rotation stabilizing period after start-up, and that updates the synchronous operation current using this output voltage or output current.

Abstract: An electrical appliance includes a housing carrying a drive motor, a temperature sensor and a controller. The temperature sensor monitors the operating temperature of the drive motor. The controller is responsive to the temperature sensor. The controller adjusts the current applied to the drive motor in response to a high temperature condition detected by the temperature sensor.

Abstract: A main power off-delay device for a power supply of a computer system is described, which comprises a control device connected to the outer power supply or disposed on a circuit board of a computer system host. Using the switch electrically coupled to a circuit of said control device and the transmitted signals, main power and standing power are continuously supplied by the power supply when the computer operational system is turned off.

Abstract: Featured is a controller for a motor that is ultra-compact, with a power density of at least about 20 watts per cubic cm (W/cm3). The controller utilizes a common ground for power circuitry, which energizes the windings of the motor, and the signal circuitry, which controls this energization responsive to signals from one or more sensors. Also, the ground is held at a stable potential without galvanic isolation. The circuits, their components and connectors are sized and located to minimize their inductance and heat is dissipated by conduction to the controller's exterior such as by a thermally conductive and electrically insulating material (e.g., potable epoxy). The controller uses a single current sensor for plural windings and preferably a single heat sensor within the controller. The body of the controller can also function as the sole plug connector.

Abstract: A speed control system is provided for controlling temperature within a chassis. The chassis includes therein a temperature sensing device for producing a temperature signal representative of temperature within the chassis, a fan, and a fan speed controller. The fan speed controller produces a nominal fan speed control signal comprising a train of pulses, successive pulses having a duty cycle related to the temperature signal produced by the temperature sensing device, such time durations decreasing with increasing temperature. The speed control system includes a decoupling circuit responsive to the nominal fan speed control signal for, in response to relatively a low duty cycle, coupling the nominal fan control signal to an output of the decoupling circuit, and, in response a relatively high duty cycle, producing a preset fan speed signal at the output of the decoupling circuit. The fan has a speed in accordance with the signal at the output of the decoupling circuit.

Abstract: A cooling device for an electrical power unit of electrically operated vehicles, comprising at least one power section and at least one control section. A first cooling circuit containing a heat exchanger with a low coolant temperature is provided mainly for cooling elements of the control sections, and a further cooling circuit with a higher coolant temperature is provided mainly for cooling elements of the power sections.

Abstract: A method for controlling a fan speed is disclosed. The fan cools a CPU in a computer. The method includes defining a CPU-max-temp value of a CPU, such that the first fan speed is linearly enhanced with the increase of a real temperature value of the CPU, when the real temperature value of the CPU is lower than the CPU-max-temp value, and changing the CPU-max-temp value to a higher CPU-max-temp value in a basic input output system. A second fan speed is linearly enhanced with an increase of the real temperature value, when the real temperature value is lower than the higher CPU-max-temp value. The second fan speed is less than the first fan speed at the real temperature value.

Abstract: The subject of the present invention is a motor control system having a monitoring circuit for monitoring PWM control for a DC electric motor, the PWM control comprising a power end stage having at least one field effect transistor, which controls the current at the DC electric motor. The motor control system is designed to monitor the current at the DC electric motor. The motor control system detects the voltage drop across the field effect transistor and comprises a temperature sensor for detecting the temperature of the field effect transistor. Furthermore, the motor control system is designed to determine the resistance of the field effect transistor from the detected temperature thereof, and to determine the current at the DC electric motor from the resistance of the field effect transistor and from the voltage drop across the field effect transistor.

Abstract: A motor control device has a drive circuit that is respectively provided on arms of an inverter circuit supplying current to an AC motor, and that drives a switching element included on the arms; and a power source control circuit that performs a control of a power supply circuit for supplying power to the drive circuit. A low-voltage circuit area is provided including the power source control circuit. A high-voltage circuit area includes one drive circuit, wherein a plurality of the high-voltage circuit areas is disposed aligned on both sides of the low-voltage circuit area such that the low-voltage circuit area is provided therebetween and also disposed with a predetermined distance provided between the high-voltage circuit area and the low-voltage circuit area. A transformer serving as the power supply circuit respectively joins the low-voltage circuit area and the high-voltage circuit areas.

Abstract: The invention relates to a method for temperature limitation according to the current and/or voltage, for an actuating device (10) associated with an electric motor (M), especially a fan regulator (12) of a motor vehicle, the temperature limitation being carried out according to at least one operating parameter of the motor (M). The invention also relates to a corresponding device (1) and a fan regulator (12).

Abstract: The present invention relates to a motor controller for an air conditioner and a motor control method. The motor controller including a converter converting AC utility power into DC power and an inverter having a plurality of switching elements, the inverter receiving the DC power, converting the received DC power into AC power by switching operations of the switching elements, and supplies the AC power to a motor, the motor controller further including: a current detector detecting a current flowing in the motor controller; a temperature detector detecting a temperature in the motor controller or a temperature ambient to the motor controller; and a controller calculating a loading based on at least one of room temperature, setup temperature, and inner unit capacity and setting up a final target frequency for driving the motor based on the calculated loading and at least one of the detected current and the detected temperature.

Abstract: Temperature of an electric drive is regulated to prevent undesirable thermal effects. Temperature conditions of the electric drive system are monitored and torque of the electric drive system is limited based on the temperature conditions.

Abstract: A running pattern of one cycle in a preset industrial machine is observed by a current detector and a temperature rise value estimating unit that are additionally provided in a traditional inverter device. The temperature rise value estimating unit derives a maximum temperature rise estimate value for each constituent element in the case where the running pattern is periodically repeated, on the basis of observation data of the one cycle and a temperature rise model of each constituent element of the inverter device.

Abstract: An electric motor controller for a vehicle has a voltage detecting section for detecting the voltage of a filter capacitor inserted on a direct current side of an inverter device including a semiconductor element for large electric power; an electric current detecting section for detecting an output electric current of the inverter device; and a temperature detecting section arranged in a cooling means of the semiconductor element for large electric power. Loss generated by a switching operation of the semiconductor element for large electric power is sequentially calculated by outputs of the detecting sections. Excessive temperature is detected when junction temperature of the large electric power semiconductor element calculated by this loss reaches an allowable temperature.

Abstract: A control circuit for a motor includes a voltage regulator having a thermal shutdown apparatus that turns off the voltage regulator while retaining power to a micro-controller preventing an automatic restart of the motor absent a recycling of power when the temperature of the control circuit rises above a pre-determined threshold level, wherein the voltage regulator is used to provide power to a plurality of insulated gate bipolar transistors controlling a plurality of stator windings of the motor. Thus the voltage regulator prevents the control circuit and the various components on the control circuit from being damaged from overheating. An embodiment of the control circuit is adapted to generate an error code in response to the shutdown of the voltage regulator and to monitor the operation of the motor to ensure that the motor has been turned off and then on before turning on the power supply to a plurality of phase windings.

Abstract: Methods and apparatus are provided for dynamic voltage control of electric motors. An inverter provides an output voltage to an electric motor based on a gate voltage. The method includes determining a speed of the electric motor and modifying the gate voltage based on the speed of the electric motor. The apparatus includes a gate drive circuit and a controller coupled to the gate drive circuit. The gate drive circuit provides a gate voltage to a switch network, and the switch network produces the output voltage in response to the gate voltage. The controller modifies the gate voltage based on a speed of the electric motor.

Abstract: A control device for controlling a recovery from a locking of a motor includes: a switching unit which supplies a motor current from a current supplying unit to the motor; and a driving control unit which supplies a PWM control signal to the switching unit to control a driving of the switching unit. The driving control unit supplies the PWM control signal with a low duty ratio lower than a regular duty ratio to the switching unit when the locking of the motor is detected depending on a variation in temperature of the switching unit. The driving control unit supplies the PWM control signal with the regular duty ratio to the switching unit when a cancel of the locking of the motor is detected depending on a variation in inter-terminal voltage of the motor.

Abstract: An automatic anti-trap device is provided to add safety to other apparatuses. The automatic anti-trap device of this invention has a driving circuit to control a motor, a current sensor to generate a current signal, a current ripple peak value circuit to generate a current ripple peak value signal according to the current signal, and a micro processor to generate a working signal for the driving circuit to control the motor according to a keystroke signal, the current signal and the current ripple peak value signal.