Electric wave clock, also known as radio controlled timer.
As a system, the technical principle of the electric wave clock is: first, the standard time signal is encoded by the standard time service center (commercial code encryption), and the time signal is broadcast by the long-wave radio station with the low-frequency (20KHz~80KHz) carrier.
The radio clock receives the low-frequency radio time code signal through the built-in micro radio receiving system, and the time code signal is demodulated by the ASIC, and then the timing of the clock is automatically adjusted by the control mechanism set in the timing device.
Through such a technical process, all clocks (or other timing devices) receiving standard time signals are highly synchronized with the standard time of the standard time service center, and then all radio clocks and watches display strictly consistent time.
Basic working principle of timing signal transmission in radio clock technology system
The timing signal transmitting part consists of an atomic clock, a time signal processor, a modulator, a carrier oscillator, an excitation stage, an amplification stage and a transmitting antenna.
Its working principle is to generate a relatively accurate and stable time-frequency standard with the atomic clock as the clock source. This frequency standard obtains real-time standard time information through the system frequency divider. Such as: year, month, day, hour, minute, second, millisecond, minute and other time information. These time information are coded, converted and encrypted by a time information processor to form a standard timing signal, and then the timing signal is sent to a modulator to modulate a high-frequency carrier. The modulated signal is used to excite the strong amplifier of the transmitter with a certain excitation power, and the strong amplifier generates tens of kilowatts of power to emit radio waves into space.
Low frequency time code service stations in different countries transmit time code signals at different frequencies.
(For example, in the United States, the time code is WWVB and the frequency is 60KHz；;
Germany, time code DCF, frequency 77.5 KHz；;
In Britain, the time code is MSF and the frequency is 60 KHz；;
Two stations in Japan, time code code JJY, frequency 40 kHz and 60 kHz; They are;
China, time code code is BPC, frequency is 68.5KHz).
Basic working principle of receiving time service signal in electric wave clock technology system
The receiver of timing signal (i.e. radio clock) is mainly composed of receiving antenna, preamplifier, tuning amplifier, automatic gain circuit, filter, demodulator, square wave shaper, time information processor, function controller and display. Its functional principle is as follows:
As a receiver, the receiving antenna of the electric wave clock receives the real-time timing signal from the time service center from space induction. Because the signal is weak, it should be sent to the tuning amplifier through the output of the front-end amplifier and amplifier for frequency-selective amplification, then filtered, shaped and filtered by the waveform shaper, and then detected and tuned, and the time signal, that is, a series of regular pulses, is extracted from the carrier, which is transformed by the receiving signal processor and sent to the display after time reduction.
The function controller sets alarm, time, temperature, humidity, voice, countdown, time period display and other functions.
4. Technical characteristics and extended application of radio wave clocks and watches
Technical characteristics of radio meter.
Compared with other time service technologies, the radio clock technology system itself can obtain high-precision standard time economically and conveniently, and meet the needs of civil standard time.
The technical principle of radio clocks and watches in all countries of the world is the same, but the adoption protocol (code system for short) of standard time signals in major countries is different. So that the radio clock in one country can't receive the signal, and the time is normally calibrated in another country. In addition, different countries and regions have different radio wave environments, and some countries, such as Germany, have little interference with radio communication. The radio environment in China and the United States is poor.
5. Extensible application of radio clock.
Radio watch technology has a wide range of applications. In addition to daily life, it can also be widely used in communication, transportation, posts and telecommunications, computers, industrial control, social life and other fields.
Radio watch technology mainly obtains standard time signal at very economical cost. Standard time is an important technical support of modern society, which can form an industry providing standard time-time technology on the basis of radio watch products.
The development of radio timing in China.
In 2000, the National Time Service Center cooperated with Xi 'an Gaohua Technology Co., Ltd. to successfully develop the BPC code (China low-frequency time code) with independent intellectual property rights in China, and conducted the experimental broadcast of the BPC code signal at the frequency of 68.5KHz on the Pucheng test bench. On March 1 day, 2002, the time service center officially began to broadcast the BPC code time service signal for 6.5 hours in two fixed time periods every day. The transmission and broadcasting of BPC code signal makes China the fifth country to master the transmission and broadcasting technology of low-frequency time code and successfully apply it to practice after Germany (DCF code), Japan (JJY code), Britain (MSF code) and the United States (WWVB code).
In 2007, the National Time Service Center cooperated with Xi 'an Gaohua Technology Co., Ltd. again to build a "BPC low-frequency time code transmitting and broadcasting station" in Shangqiu, Henan. The transmitting power of this station is 100KW, the frequency is 68.5KHz, the tower height is 249M, and the daily broadcasting time is 2 1 hour. The coverage radius of BPC code ground wave signal is 1000KM, and the coverage radius of sky wave signal can reach 3000KM, covering most population areas and administrative areas in China.