Abstract: A digital self-injection-locked (SIL) radar includes a digital SIL oscillator, a wireless signal transceiver and a digital frequency demodulator. The digital SIL oscillator generates a digital output signal. The wireless signal transceiver is electrically connected to the digital SIL oscillator to convert the digital output signal into a wireless signal for transmission to a target, receives a reflected signal from the target, and converts the reflected signal into a digital injection signal for injection into the digital SIL oscillator. Accordingly, the digital SIL oscillator operates in an SIL state and generates a digital oscillation signal. The digital frequency demodulator is electrically connected to the digital SIL oscillator to receive and demodulate the digital oscillation signal into a digital demodulation signal.

Abstract: A phase-tracking self-injection-locked (SIL) radar includes an SIL oscillator, a phase-tracking SIL loop and a frequency-locked loop. The SIL oscillator generates an electrical oscillation signal and receives an electrical injection signal related to the electrical oscillation signal for self-injection locking. The phase-tracking SIL loop receives the electrical oscillation signal and outputs the electrical injection signal to the SIL oscillator with a constant phase difference between the electrical oscillation signal and the electrical injection signal. The frequency-locked loop receives the electrical oscillation signal and produces an electrical control signal to control the phase-tracking SIL loop or the SIL oscillator for eliminating the frequency shift of the SIL oscillator caused by the phase-tracking SIL loop.

Abstract: A phase-tracking self-injection-locked (SIL) radar includes an SIL oscillator, a phase-tracking SIL loop and a frequency-locked loop. The SIL oscillator generates an electrical oscillation signal and receives an electrical injection signal related to the electrical oscillation signal for self-injection locking. The phase-tracking SIL loop receives the electrical oscillation signal and outputs the electrical injection signal to the SIL oscillator with a constant phase difference between the electrical oscillation signal and the electrical injection signal. The frequency-locked loop receives the electrical oscillation signal and produces an electrical control signal to control the phase-tracking SIL loop or the SIL oscillator for eliminating the frequency shift of the SIL oscillator caused by the phase-tracking SIL loop.

Abstract: A digital self-injection-locked (SIL) radar includes a digital SIL oscillator, a wireless signal transceiver and a digital frequency demodulator. The digital SIL oscillator generates a digital output signal. The wireless signal transceiver is electrically connected to the digital SIL oscillator to convert the digital output signal into a wireless signal for transmission to a target, receives a reflected signal from the target, and converts the reflected signal into a digital injection signal for injection into the digital SIL oscillator. Accordingly, the digital SIL oscillator operates in an SIL state and generates a digital oscillation signal. The digital frequency demodulator is electrically connected to the digital SIL oscillator to receive and demodulate the digital oscillation signal into a digital demodulation signal.

Abstract: A motor speed control having synchronous PWM signals has a synchronous phase detecting unit and a PWM control unit. The synchronous phase detecting unit detects the phase variation of a Hall signal, which represents the phase change of the motor, and outputs a digital value to the PWM control unit. The PWM control unit compares the digital value with a speed control command so as to obtain a PWM signal, wherein the PWM signal is synchronized with the Hall signal. Since the PWM signal is synchronized with the Hall signal, the motor is operated smoothly even in the low speed rotation, and audible noises are effectively reduced.

Abstract: A motor speed control having synchronous PWM signals has a synchronous phase detecting unit and a PWM control unit. The synchronous phase detecting unit detects the phase variation of a Hall signal, which represents the phase change of the motor, and outputs a digital value to the PWM control unit. The PWM control unit compares the digital value with a speed control command so as to obtain a PWM signal, wherein the PWM signal is synchronized with the Hall signal. Since the PWM signal is synchronized with the Hall signal, the motor is operated smoothly even in the low speed rotation, and audible noises are effectively reduced.