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What is a radio controlled clock?

What is a radio controlled clock?

28 Aug 2020

Radio controlled timepieces, also known as wireless control timepieces, are a new generation of high-tech products following quartz electronic clocks. The radio-controlled clock is a quartz electronic clock with a functional structure of receiving radio carrier signal, data processing, and automatic correction. In this way, it can receive the standard time signal sent by the ground transmitting station with the carrier wave. When the radio wave clock receives this precise time code and is processed by the data processor, it can automatically correct the time error of the radio wave clock. Finally, each radio wave The clock running ability is controlled by a unified and accurate time code, thus realizing the high-precision measurement and display time consistency of all radio-controlled clocks.

Principle of Radio Controlled Clock

As for the principle of Radio Controlled Clock Technology System, first of all, the standard time signal is encoded by the standard time of the time service center (the commercial code is encrypted), and the time signal is broadcasted in long radio waves using low-frequency (20KHz~80KHz) carrier mode. The radio-controlled timepiece receives the low-frequency radio time code signal through the built-in miniature radio receiving system, and then demodulates the time code signal by a dedicated integrated chip. Finally, the control mechanism in the timing device automatically adjusts the timing of the timepiece. Through such a technical process, all clocks (or other timing devices) that receive the standard time signal are highly synchronized with the standard time from the time service center. Only in this way, all radio-controlled clocks display strictly consistent time.

Working principle of timing signal transmission

The transmitting part of the timing signal is composed of an atomic clock, a time signal processor, a modulator, a carrier oscillator, an excitation stage, a strong amplifier stage and a transmitting antenna.

In terms of the emission principlethe atomic clock is used as the clock source to produce a relatively accurate and stable time-frequency standard. This frequency standard obtains real-time standard time information through the system frequency divider. Such as: year, month, day, hour, minute, second, millisecond, subtle and other time information, those time information will be processed by the time information processor for code conversion and encryption to form a standard timing signal, and then the timing signal is sent to the modulator to modulate a high-frequency carrier. The modulated signal passes through the exciter with a certain excitation power to excite the strong release stage of the transmitter, the strong release stage generates tens of kilowatts of power to emit radio waves into space.

Low-frequency time code timing stations in different countries transmit time code signals at different frequencies. (For example: the United States, the time code code is WWVB, and the frequency is 60KHz; Germany, the time code code is DCF, and the frequency is 77.5 KHz; the United Kingdom, the time code code is MSF, and the frequency is 60 KHz; two stations in Japan, the time code code is JJY , The frequency is 40 KHz and 60 KHz respectively; China, the time code code is BPC, the frequency is 68.5KHz)

Working principle of timing signal receiving

The receiver of the timing signal (ie, radio wave clock) is mainly composed of receiving antenna, preamplifier, tuning amplifier, automatic gain circuit, filter, demodulator, square wave former, time information processor, function controller and display.

Its functional principle like this, as a receiver, the receiving antenna of the radio wave clock receives the real-time timing signal transmitted by the timing center from the space induction. Because the signal is weak, the output of the front-end amplifier and the transmitter is sent to the tuning amplifier for frequency selective amplification, and then filtered. The waveform former is reshaped, filtered, and then detected and tuned. The time signal is extracted from the carrier, that is, a series of regular pulses. The pulses are then transformed by the receiving signal processor. When the time is restored, they are sent to Go to the monitor for display. Finally, the function controller sets its functions, such as: alarm, time signal, temperature, humidity, voice, countdown, time period display, etc.

Reasons for unsuccessful timing

1. The position where the clock is located is weak, or there are strong electromagnetic interference signals nearby. Please select a location where it is easier to receive signals and a location free from other electromagnetic interference;

2. The radio wave signal is not transmitted 24 hours a day, and the transmission will be interrupted due to maintenance operations, thunderstorms, lightning and other factors. If the signal cannot be received normally at this time, please receive at another time;

3. The battery power is low, please replace with a new battery;

4. Clock failure. If the location of the area is within the signal reception area, try to adjust the receiving position and the receiving time point multiple times. Both methods fail to correct the time. The above situation indicates that the clock has failed.

What environmental factors affect signal reception?

The use of a radio wave clock in a special environment may result in failure to receive signals normally. When selecting a receiving location, choose a location that is easy to receive signals and does not interfere with electromagnetic signals, such as near an indoor window. The following environment should be avoided as follows:

1. The densely-built buildings or high-rise buildings will shield the signal;

2. Places with severe electromagnetic interference (such as high-voltage lines, household appliances, computers, mobile phones, etc.);

3. Radio waves in the valley are shielded by the terrain from the signal.

The radio-wave timing technology is the mainstream

As a new emerging technology, radio wave time service has all parameters far beyond the existing quartz clock timekeeping. Its technology is relatively simpler than GPS, lower in price, and high in time service accuracy. It has gradually demonstrated its superiority in many fields and is in line with future timing development trends. National conditions require. Moreover, in other developed countries such as the United States, Japan, Britain, and Germany, the application and popularization of radio-wave timing technology have confirmed that radio-wave timing technology is the mainstream of future timekeeping products.

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