El principio de fase fotoeléctrico rango buscador
El principio de funcionamiento de la fase fotoeléctrico rango buscador puede ser explicado de acuerdo a el bloque diagrama mostrado en la figura.
The light wave (infrared light or laser) emitted by the light source enters the modulator and is modulated by the high-frequency ranging signal from the master oscillator (referred to as the master oscillator) to become an amplitude modulated wave. the amplitude-modulated wave enters the receiver through the external optical path and converges on the photoelectric device, and the optical signal is immediately converted into an electrical signal. This electrical signal is the demodulated high-frequency ranging signal after the AM wave travels back and forth to the survey line, and its phase has been delayed.
The high-frequency ranging signal and the high-frequency signal from the local oscillator (abbreviated as local oscillator) are photoelectrically mixed by the ranging signal mixer, and a low-frequency ranging signal is obtained after frequency-selective amplification, denoted by . The original phase delay of the high-frequency ranging signal is still preserved. In order to perform phase comparison, a part of the high-frequency ranging signal of the main oscillator is called the reference signal and the high-frequency signal of the local oscillator is sent to the reference signal mixer at the same time. After frequency selection and amplification, a low-frequency reference signal that can be used as a reference for phase comparison is obtained. It means that there is no phase delay as in the image because there is no round trip to and from the survey line. Therefore, the phase delay result of the ranging signal from and to the measuring line will be displayed on the display when the digital phase measuring technology is used for phase comparison with the phase device sent at the same time.
When a measuring ruler frequency is used, there is only the mantissa corresponding to the phase difference of less than one week on the display, and the number of whole feet corresponding to the number of full cycles exceeding one week cannot be known. Para este motivo, la fase telémetro El dos componentes de la principal vibración y la local vibración también incluya a set de oscilación frecuencias de la gruesa escala, es, la principal vibración frecuencia y la local vibración frecuencia. As mencionado antes, if la misma medición es hecha con la frecuencia de la escala gruesa 2c la resultados de la fina escala y a set de gruesa escalas are combinadas a obtener el valor de todo distancia a ser medido.
