CN114326362A - Wireless time service system and method parasitizing on FM radio station - Google Patents
Wireless time service system and method parasitizing on FM radio station Download PDFInfo
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Abstract
The application relates to a wireless time service system and a method parasitizing on a frequency modulation radio station. The system comprises: a transmitting end and a receiving end; the transmitting terminal is obtained by adding a time coder and a signal synthesizer on the basis of the transmitting terminal of the original FM radio station, and the carrier frequency signal of the transmitting terminal is a sine wave with the frequency of 1 kHz; the time coder is used for coding the UTC time signal in a self-defined coding mode to obtain a time coding signal with the frequency of 10Hz and the code element length of 10 whole periods, and the signal synthesizer is used for synthesizing the time coding signal and the voice signal to be modulated into a synthesized signal; the demodulator at the receiving end is configured to demodulate the modulated composite signal to obtain a demodulated composite signal, where the demodulated composite signal includes a time-coded signal and an audio signal. When the system is used for timing local equipment, the construction cost of the timing system is low, the coverage is wide, and the timing accuracy is high.
Description
Technical Field
The present application relates to the field of time synchronization technologies, and in particular, to a wireless time service system and method hosted by a fm radio station.
Background
Time service is to transmit time information, and strictly speaking, a standard time signal is transmitted to a user (including but not limited to a mobile phone, a computer, a television and the like) needing time information, so that the time of the whole system is synchronized. In short, when you find that the time of the mobile phone is slow by several seconds, the time service is calculated by referring to the process of computer time calibration. When time is needed, a uniform standard time is needed. Meanwhile, the time service technology is accompanied with the continuous development of the human society. The current time service method mainly comprises the following aspects: radio time service, network time service, satellite time service and optical fiber time service.
At present, the time service technologies need to adopt special equipment or transmission lines, or special professional frequency band resources, or special optical fiber transmission, and at present, a method for performing time service by using a frequency modulation radio station is also proposed, and an SCA1 additional channel of the frequency modulation radio station is also used, and the frequency resources need to be occupied independently. The conventional wired transmission mode has limited distance, the cost is high when the transmission distance is long, the wireless transmission generally adopts a long-wave or short-wave fixed-frequency transmission mode, a special long-wave and short-wave transmitting base is required, the cost is high, and the coverage range is limited.
Disclosure of Invention
In view of the above, there is a need to provide a wireless time service system and method for a fm radio station, which can implement high-precision time service by using a fm radio station spurious signal without occupying additional frequency resources and bandwidth.
A wireless time service system hosted by a fm station, the system comprising: a transmitting end and a receiving end; and the transmitting end and the receiving end carry out data transmission through radio waves.
The transmitting terminal is obtained by improving the transmitting terminal of the original FM radio station, and the improvement points are as follows: adding a time coder and a signal synthesizer; the carrier frequency signal of the transmitting end is a sine wave with the frequency of 1 kHz.
The time encoder is used for encoding the UTC time signal by adopting a self-defined encoding mode to obtain a time encoding signal, and inputting the time encoding signal and the voice signal to be modulated of the radio station into the signal synthesizer; the frequency of the time-coded signal is 10Hz, and the length of the code element is 10 whole periods.
The signal synthesizer is used for synthesizing the received voice signal to be modulated of the radio station and the time coding signal into a synthesized signal and inputting the synthesized signal into the modulator.
The receiving end comprises a demodulator; the demodulator is configured to demodulate a received composite signal modulated by the modulator to obtain a demodulated composite signal, where the demodulated composite signal includes a demodulated time-coded signal and an audio signal.
Furthermore, the receiving end also comprises a signal splitter, a 20Hz low-pass filter and a time service signal decoding module.
The signal splitter is used for splitting the demodulated synthetic signal into two paths of demodulated synthetic signals, taking the first path of demodulated synthetic signal as an audio signal for subsequent processing, and inputting the second path of demodulated synthetic signal into the 20Hz low-pass filter.
And the 20Hz low-pass filter is used for performing low-pass filtering on the received second path of demodulated composite signal to obtain a demodulated time coding signal.
And the time service signal decoding module is used for decoding the received demodulated time coding signal to obtain a decoded UTC time signal.
Further, the time encoder adopts a self-defined encoding mode as follows: the initial bit is 1bit, the last two bits of the year occupy 7bits, the month occupies 4bits, the day occupies 5bits, the total seconds in the day occupy 17bits, and the total time is 34 bits; the symbols of the time-coded signal comprise: the device comprises a P code element, an H code element and an L code element, wherein the P code element represents the start of frame data, is a starting bit and is also a starting point of a whole minute and used for accurately aligning a time point; the H symbol represents the number 1; the L symbol represents a number 0; the code element length is fixed to 1 second and consists of 10 full-period 10Hz signals; p symbols when the ratio of the high level duration to the low level duration of the amplitude is 4:1, H symbols when the ratio of the high level duration to the low level duration of the amplitude is 1:1, and L symbols when the ratio of the high level duration to the low level duration of the amplitude is 1: 4; the interior of the code element adopts an ASK modulation mode, and the modulation proportion is configurable.
Further, the pair of orthogonal signals includes: a sine signal and a cosine signal.
The time service signal decoding module comprises two decoding branches consisting of a first multiplier, 1 low-pass filter and a second multiplier, 1 adder, 1 comparator and 1 counting mode decoding module;
and the first decoding branch is used for receiving the sinusoidal signal and the demodulated time coding signal, multiplying the sinusoidal signal and the demodulated time coding signal by the first multiplier, filtering the obtained multiplied signal by the low-pass filter, and squaring the filtered signal by the second multiplier to obtain a sinusoidal demodulation signal.
And the second decoding branch is used for performing cosine demodulation on the demodulated time coding signal by using the cosine signal to obtain a cosine demodulation signal.
And the adder is used for adding the sine demodulation signal and the cosine demodulation signal to obtain a sum signal.
The comparator is used for comparing the summation signal with a preset threshold level.
And the decoding module of the counting mode is used for carrying out high-level counting on the signal output by the comparator, determining the code element type according to the obtained counting value, decoding the code element of the time coding signal according to the code element type and obtaining the time service information according to the obtained decoded time coding signal.
Further, obtaining time service information according to the decoded time-coded signal includes:
and determining an original starting time point from the rising edge of the P code element of the demodulated time coding signal, and compensating the original starting time of minutes to obtain the starting time point.
And decoding according to 33 code elements following the P code in the demodulated time coding signal to obtain an accurate UTC time value corresponding to the starting time point.
And the starting time point and the corresponding accurate UTC time value form complete time service information to complete time service on the local equipment.
Further, the 20Hz low-pass filter is a switched capacitor filter.
Further, the signal synthesizer includes an adder.
A wireless time service method parasitizing on a frequency modulation radio station is used for carrying out time service on a user by adopting any one of the wireless time service systems parasitizing on the frequency modulation radio station; the method comprises the following steps:
a transmitting end:
the sine wave with the frequency of 1kHz is used as a carrier frequency signal, and a UTC time signal is coded in a self-defined coding mode to obtain a time coding signal with the frequency of 10Hz and the code element length of 10 whole periods.
And synthesizing the time coding signal and the voice signal to be modulated of the radio station by adopting a signal synthesizer to obtain a synthesized signal.
And modulating the synthesized signal to obtain a modulated synthesized signal, and sending the modulated synthesized signal to a receiving end through radio waves.
Receiving end:
and receiving the modulated and synthesized signal, and demodulating the modulated and synthesized signal by adopting a pair of orthogonal signals with the same frequency as the carrier frequency signal of the transmitting end to obtain a demodulated and synthesized signal, wherein the demodulated and synthesized signal comprises a demodulated time coding signal and an audio signal.
When a receiving end needs to normally receive a time signal, dividing the demodulated composite signal into two paths of signals, and inputting the first path of signal serving as an audio signal into an audio signal subsequent processing module; and filtering the second path of signals by adopting a 20Hz low-pass filter to obtain demodulated time coding signals, and decoding the demodulated time coding signals to obtain UTC time signals.
The above-mentioned wireless time service system and method parasitizing on FM radio station, the said system includes: a transmitting end and a receiving end; the transmitting end and the receiving end carry out data transmission through radio waves; the transmitting terminal is obtained by improving the transmitting terminal of the original FM radio station, and the improvement points are as follows: adding a time coder and a signal synthesizer; the carrier frequency signal of the transmitting end is a sine wave with the frequency of 1kHz, and the receiving end comprises a demodulator. The time coder is used for coding the UTC time signal in a self-defined coding mode to obtain a time coding signal, and the signal synthesizer is used for synthesizing the time coding signal and a voice signal to be modulated of the radio station to obtain a synthesized signal; wherein the time-encoded signal has a frequency of 10Hz and a symbol length of 10 full periods. The demodulator is configured to demodulate the modulated composite signal to obtain a demodulated composite signal, where the demodulated composite signal includes the demodulated time-coded signal and the audio signal. The system can generate sub-millisecond level without occupying extra frequency and bandwidth resources
The time service signal is used for time service for the local equipment; under the existing basic design conditions, the system can realize the nationwide full-coverage time service mode by slight modification, and the cost is reduced.
Drawings
FIG. 1 is a block diagram of a wireless timing system hosted by a FM station, according to one embodiment;
FIG. 2 is a spectral structure of a synthesized signal in another embodiment;
FIG. 3 is a block diagram of a receiving end in another embodiment;
FIG. 4 is a diagram of three symbols in another embodiment, wherein (a) is a P symbol, (b) is an H symbol, and (c) is an L symbol;
FIG. 5 is a block diagram of a time signal decoding module according to another embodiment;
fig. 6 is a flow diagram illustrating a method for wireless time service by a fm station, according to an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
In general, the frequency range of a speech signal is: 300 Hz-3.4 kHz, and is widened to the professional audio field, and the frequency range of the audio signal is as follows: 20 Hz-20 kHz, i.e. meaning frequencies below 20Hz, which are not audible at all by the human ear, have no way to transmit speech signals, but from another point of view, the frequency band below 20Hz can still be used to convey some other useful information, which is the use of the low frequency band of fm radio stations to transmit time signals.
The time service signal generally needs to transmit accurate and perfect time information, which contains information of two aspects, namely, an accurate time alignment signal, that is, a time point, on one hand, and information of the other aspect is an accurate UTC time value corresponding to the time point. The situation of the channel being unidirectional or bidirectional can be divided into unidirectional time service and bidirectional comparison time service, and the signal transmitted by the radio station is unidirectional, so that only the unidirectional time service situation is considered. The most common method in unidirectional time service is a wired transmission 1PPS + TOD transmission method, namely, the transmission method adopts time point and time code division to be two channels. Of course, there are many transmission methods that combine the time point and the time code to transmit them through one channel, such as B code, which is divided into ac B code and dc B code, and the method is to merge the two information into one channel for transmission. The coding mode of the invention refers to the design idea of the alternating current B code, the signal frequency of the alternating current B code is 1kHz, but the frequency signal is in an audio frequency range, the frequency of the alternating current B code can be correspondingly reduced to 10Hz, the coding mode adopts custom coding, and the corresponding time service frequency is expanded to one time service of 60 seconds.
In one embodiment, as shown in fig. 1, there is provided a wireless time service system hosted by a fm station, the system comprising: a transmitting end 10 and a receiving end 20; the transmitting end 10 and the receiving end 20 perform data transmission through radio waves.
The transmitting terminal 10 is obtained by improving the original transmitting terminal of the fm radio station, that is, only a voice signal to be modulated of the radio station and a time code signal are synthesized and then changed into a synthesized signal to be input to the modulator, and the spectrum structure of the synthesized signal is as shown in fig. 2. The concrete improvement points are as follows: adding a time encoder 101 and a signal synthesizer 102; the carrier frequency signal of the transmitting terminal 10 is a sine wave with a frequency of 1 kHz.
The time encoder 101 is configured to encode the UTC time signal in a custom encoding manner to obtain a time encoded signal, and input the time encoded signal and a speech signal to be modulated of the radio station into the signal synthesizer; the time-coded signal has a frequency of 10Hz and a symbol length of 10 full periods.
The signal synthesizer 102 is configured to synthesize the received speech signal to be modulated of the radio station and the time code signal into a synthesized signal, and input the synthesized signal into the modulator.
The receiving end 20 includes a demodulator 201; the demodulator 201 is configured to demodulate the received composite signal modulated by the modulator to obtain a demodulated composite signal, where the demodulated composite signal includes a demodulated time-coded signal and an audio signal.
Specifically, at the receiving end, if a signal is received by a common radio, no change is made, because the demodulated signal is a composite signal of a radio station audio signal and a time coding signal, the frequency spectrum structure of the composite signal is as shown in fig. 2, the frequency dimension of the composite signal of the time coding signal is 10Hz, the composite signal is not in the audio frequency range, no feeling is given to the ear, only the radio station audio signal is heard,
in the above wireless time service system parasitic on the fm station, the system includes: a transmitting end and a receiving end; the transmitting end and the receiving end carry out data transmission through radio waves; the transmitting terminal is obtained by improving the transmitting terminal of the original FM radio station, and the improvement points are as follows: adding a time coder and a signal synthesizer; the carrier frequency signal of the transmitting end is a sine wave with the frequency of 1kHz, and the receiving end comprises a demodulator. The time coder is used for coding the UTC time signal in a self-defined coding mode to obtain a time coding signal, and the signal synthesizer is used for synthesizing the time coding signal and a voice signal to be modulated of the radio station to obtain a synthesized signal; wherein the time-encoded signal has a frequency of 10Hz and a symbol length of 10 full periods. The demodulator is configured to demodulate the modulated composite signal to obtain a demodulated composite signal, where the demodulated composite signal includes the demodulated time-coded signal and the audio signal. The system can generate sub-millisecond level without occupying extra frequency and bandwidth resources
The time service signal is used for time service for the local equipment; under the existing basic design conditions, the system can realize the nationwide full-coverage time service mode by slight modification, and the cost is reduced.
Further, as shown in fig. 3, the receiving end further includes a signal splitter 202, a 20Hz low pass filter 203, and a time signal decoding module 204; a signal splitter 202, configured to split the demodulated composite signal into two paths of demodulated composite signals, use the first path of demodulated composite signal as an audio signal for subsequent processing, and input the second path of demodulated composite signal into a 20Hz low-pass filter 203; the 20Hz low-pass filter 203 is used for performing low-pass filtering on the received second path of demodulated composite signal to obtain a demodulated time coding signal; and a time service signal decoding module 204, configured to decode the demodulated time coding signal to obtain a decoded UTC time signal.
Specifically, if the receiving end needs to receive the time signal normally, the demodulated composite signal is divided into two paths, one path is directly an audio signal and is sent to the audio signal for subsequent processing, the other path passes through a low-pass filter, the cut-off frequency of the low-pass filter can be set to be 20Hz, and a switched capacitor filter is preferably adopted. The filtered audio signal is rate removed leaving only a 10Hz time encoded signal. And recovering the UTC time signal by decoding.
Further, the time encoder adopts a self-defined encoding mode as follows: the initial bit is 1bit, the last two bits of the year occupy 7bits, the month occupies 4bits, the day occupies 5bits, the total seconds in the day occupy 17bits, and the total time is 34 bits; the symbols of the time-coded signal comprise: the device comprises a P code element, an H code element and an L code element, wherein the P code element represents the start of frame data, is a starting bit and is also a starting point of a whole minute and used for accurately aligning a time point; the H symbol represents the number 1; the L symbol represents a number 0; the code element length is fixed to 1 second and consists of 10 full-period 10Hz signals; p symbols when the ratio of the high level duration to the low level duration of the amplitude is 4:1, H symbols when the ratio of the high level duration to the low level duration of the amplitude is 1:1, and L symbols when the ratio of the high level duration to the low level duration of the amplitude is 1: 4; the interior of the code element adopts an ASK modulation mode, and the modulation proportion is configurable.
Specifically, the time length of the H symbol with the high amplitude is 800ms (8 whole periods), the time length of the H symbol with the low amplitude is 200ms (2 whole periods), the time length of the H symbol with the high amplitude is 500ms (5 whole periods), the time length of the L symbol with the low amplitude is 500ms (5 whole periods), the time length of the L symbol with the high amplitude is 200ms (2 whole periods), the time length of the L symbol with the low amplitude is 800ms (8 whole periods), and the amplitude-to-height ratio (a)H/AL) The modulation ratio is called as a modulation ratio, and can be configured according to actual requirements, and the modulation ratio is selected from 3: 1; the signal amplitude can flexibly configure the gain and attenuation according to the modulation needs of the station, and the specific code elements are shown in fig. 4, wherein (a) is P code element, (b) is H code element, and (c) isAnd L code elements.
Further, as shown in fig. 5, a structure of the time signal decoding module is shown. A pair of orthogonal signals includes: a sine signal and a cosine signal. The time service signal decoding module comprises two decoding branches consisting of a first multiplier, 1 low-pass filter and a second multiplier, 1 adder, 1 comparator and 1 counting mode decoding module; the first decoding branch is used for receiving the sinusoidal signal and the demodulated time coding signal, multiplying the sinusoidal signal and the demodulated time coding signal through a first multiplier, filtering the obtained multiplied signal through a low-pass filter, and squaring the filtered signal through a second multiplier to obtain a sinusoidal demodulation signal; and so on, the second decoding branch is used for performing cosine demodulation on the demodulated time coding signal by adopting a cosine signal to obtain a cosine demodulation signal; the adder is used for adding the sine demodulation signal and the cosine demodulation signal to obtain a sum signal; a comparator for comparing the summed signal with a preset threshold level; and the counting type decoding module is used for carrying out high-level counting on the signal output by the comparator, determining the code element type according to the obtained counting value, decoding the code element of the time coding signal according to the code element type and obtaining the time service information according to the decoded time coding signal.
Specifically, the three symbol diagrams depicted in FIG. 4, each symbol may be represented by the function S (t)1,t2)＝AHsin(2π·t1/T)+ALsin(2π·t2T), where T is the period of the symbol, T100 ms, T1∈[t0,t0+nT]，t2∈[t0+nT,t0+10T]Note that, for the P symbol, n is 8, for the H symbol, n is 5, and for the L symbol, n is 2, the schematic diagram of the timing signal decoding module on the receiving side is shown in fig. 5, where LPF in fig. 5 represents a low pass filter.
The receiving end generates a pair of orthogonal signals of the same frequency as the carrier frequency of the transmitting end,
wherein the content of the first and second substances,
considering a method for demodulating a symbol for initial phase, a signal S is obtained by multiplying an orthogonal signal with an input symbolI(t)、SQ(t) the expression is shown in formula (1).
Wherein, t1、t2Are all time variables, t0N is a number of cycles, n is an integer of 1 to 10 inclusive, and T is a symbol period.
Will be provided with
Substitution into formula (1) gives formula (2) and formula (3).
The expressions of the signals obtained by integrating and subtracting the expressions (2) and (3) and filtering the signals by a low-pass filter (filtering the signals higher than 20 Hz) are shown as the expressions (4) and (5).
Wherein, S'I(t)、S'Q(t) are respectively the signal SI(t)、SQ(t) filtered informationNumber AHIs a high amplitude value of the symbol, ALIs a low amplitude value of the symbol.
An expression of a signal obtained by squaring and summing the signals represented by the formulae (4) and (5) is shown in the formula (6).
As can be seen from equation (6), two DC levels can be obtained for the result after single symbol demodulation, with the high level being
At a low level of
If the ratio of the high level to the low level is 4:1 is P code element, the ratio of high level to low level is 1:1 is H code element, the ratio of high level to low level is 1: and 4, the code element is an L code element, the identification method is simpler, for example, a reasonable comparison threshold can be adopted, only a high level trigger counter is used for counting, because the length of the code element is fixed, and the type of the code element can be judged through the counting value. The comparator extracts the high level pulse of P, H and L code elements of 800ms, 500ms and 200ms for subsequent decoding and identification, and the decoding only needs to count the width of the pulse, namely P code if about 800ms, H code if about 500ms, and L code if about 200 ms. The preset threshold level is set according to the principle that the recognition degree of the code element is maximized, and the intermediate value between the two levels is optimal.
In the derivation of the above formula, if a small frequency difference exists between the generation of the orthogonal carrier signal at the receiving end and the sine wave at the transmitting end, the same result can be obtained if the two signals are completely orthogonal.
In one embodiment, obtaining the timing information according to the decoded time-coded signal includes: determining an original starting time point from the rising edge of the P code element of the demodulated time coding signal, and compensating the original starting time of minutes to obtain the starting time point; decoding according to 33 code elements following the P code in the demodulated time coding signal to obtain an accurate UTC time value corresponding to the starting time point; and the starting time point and the corresponding accurate UTC time value form complete time service information to complete time service on the local equipment.
Specifically, the demodulation of the time service code stream signal is divided into two processes, firstly, an initial signal of a whole minute is provided, and the rising edge of the demodulated P code is the initial signal of the minute, so that the signal processing has a certain time delay, but the time delay is changed into a fixed time delay, the time delay can be compensated in a deduction mode, and the precision after the compensation can reach the sub-millisecond order. And secondly, the specific year, month, day, time, minute and second is solved according to 33 code elements following the P code, so that complete time service information is obtained, an accurate time point is provided, a determined time code is provided, and time service can be performed on local equipment.
Further, the 20Hz low-pass filter is a switched capacitor filter.
Further, the signal synthesizer includes an adder.
In one embodiment, as shown in fig. 6, a method for providing time service to a user by using any of the above-mentioned wireless time service systems hosted by a fm station is provided; the method comprises the following steps:
a transmitting end:
step 600: the sine wave with the frequency of 1kHz is used as a carrier frequency signal, and a UTC time signal is coded in a self-defined coding mode to obtain a time coding signal with the frequency of 10Hz and the code element length of 10 whole periods.
Step 602: and synthesizing the time coding signal and the voice signal to be modulated of the radio station by adopting a signal synthesizer to obtain a synthesized signal.
Step 604: and modulating the synthesized signal to obtain a modulated synthesized signal, and transmitting the modulated synthesized signal to a receiving end through radio waves.
Receiving end:
step 606: and receiving the modulated and synthesized signal, and demodulating the modulated and synthesized signal by adopting a pair of orthogonal signals with the same frequency as the carrier frequency signal of the transmitting end to obtain a demodulated and synthesized signal, wherein the demodulated and synthesized signal comprises a demodulated time coding signal and an audio signal.
Step 608: when the receiving end needs to normally receive the time signal, the demodulated composite signal is divided into two paths of signals, and the first path of signal is used as an audio signal and input into an audio signal subsequent processing module; and filtering the second path of signals by adopting a 20Hz low-pass filter to obtain demodulated time coding signals, and decoding the demodulated time coding signals to obtain UTC time signals.
It should be understood that, although the steps in the flowchart of fig. 6 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least a portion of the steps in fig. 6 may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, and the order of performance of the sub-steps or stages is not necessarily sequential, but may be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (8)
1. A wireless time service system for a fm station, the system comprising: a transmitting end and a receiving end; the transmitting end and the receiving end carry out data transmission through radio waves;
the transmitting terminal is obtained by improving the transmitting terminal of the original FM radio station, and the improvement points are as follows: adding a time coder and a signal synthesizer; the carrier frequency signal of the transmitting end is a sine wave with the frequency of 1 kHz;
the time encoder is used for encoding the UTC time signal by adopting a self-defined encoding mode to obtain a time encoding signal, and inputting the time encoding signal and the voice signal to be modulated of the radio station into the signal synthesizer; the frequency of the time coding signal is 10Hz, and the length of the code element is 10 whole periods;
the signal synthesizer is used for synthesizing the received voice signal to be modulated of the radio station and the time coding signal into a synthesized signal and inputting the synthesized signal into the modulator;
the receiving end comprises a demodulator; the demodulator is configured to demodulate a received composite signal modulated by the modulator to obtain a demodulated composite signal, where the demodulated composite signal includes a demodulated time-coded signal and an audio signal.
2. The system according to claim 1, wherein the receiving end further comprises a signal splitter, a 20Hz low pass filter and a time service signal decoding module;
the signal splitter is used for splitting the demodulated synthetic signal into two paths of demodulated synthetic signals, taking the first path of demodulated synthetic signal as an audio signal for subsequent processing, and inputting the second path of demodulated synthetic signal into the 20Hz low-pass filter;
the 20Hz low-pass filter is used for performing low-pass filtering on the received second path of demodulated composite signal to obtain a demodulated time coding signal;
and the time service signal decoding module is used for decoding the received demodulated time coding signal to obtain a decoded UTC time signal.
3. The system of claim 2, wherein the time encoder uses a custom coding scheme that is: the initial bit is 1bit, the last two bits of the year occupy 7bits, the month occupies 4bits, the day occupies 5bits, the total seconds in the day occupy 17bits, and the total time is 34 bits; the symbols of the time-coded signal comprise: the device comprises a P code element, an H code element and an L code element, wherein the P code element represents the start of frame data, is a starting bit and is also a starting point of a whole minute and used for accurately aligning a time point; the H symbol represents the number 1; the L symbol represents a number 0; the code element length is fixed to 1 second and consists of 10 full-period 10Hz signals; p symbols when the ratio of the high level duration to the low level duration of the amplitude is 4:1, H symbols when the ratio of the high level duration to the low level duration of the amplitude is 1:1, and L symbols when the ratio of the high level duration to the low level duration of the amplitude is 1: 4; the interior of the code element adopts an ASK modulation mode, and the modulation proportion is configurable.
4. The system of claim 3, wherein a pair of orthogonal signals comprises: a sine signal and a cosine signal;
the time service signal decoding module comprises two decoding branches consisting of a first multiplier, 1 low-pass filter and a second multiplier, 1 adder, 1 comparator and 1 counting mode decoding module;
the first decoding branch is used for receiving the sinusoidal signal and the demodulated time coding signal, multiplying the sinusoidal signal and the demodulated time coding signal by the first multiplier, filtering the obtained multiplied signal by the low-pass filter, and squaring the filtered signal by the second multiplier to obtain a sinusoidal demodulation signal;
and so on, the second decoding branch is used for performing cosine demodulation on the demodulated time coding signal by using the cosine signal to obtain a cosine demodulation signal;
the adder is used for adding the sine demodulation signal and the cosine demodulation signal to obtain a sum signal;
the comparator is used for comparing the summation signal with a preset threshold level;
and the decoding module of the counting mode is used for carrying out high-level counting on the signal output by the comparator, determining the code element type according to the obtained counting value, decoding the code element of the time coding signal according to the code element type and obtaining the time service information according to the obtained decoded time coding signal.
5. The system of claim 3, wherein deriving timing information from the decoded time-coded signal comprises:
determining an original starting time point from the rising edge of the P code element of the demodulated time coding signal, and compensating the original starting time of minutes to obtain the starting time point;
decoding according to 33 code elements following the P code in the demodulated time coding signal to obtain an accurate UTC time value corresponding to the starting time point;
and the starting time point and the corresponding accurate UTC time value form complete time service information to complete time service on the local equipment.
6. The system of claim 2, wherein the 20Hz low pass filter is a switched capacitor filter.
7. The system of any of claims 1-6, wherein the signal synthesizer comprises an adder.
8. A method of wireless time service on a fm radio station, the method being used to time a user using the system of any one of claims 1 to 7; the method comprises the following steps:
a transmitting end:
adopting a sine wave with the frequency of 1kHz as a carrier frequency signal, and coding the UTC time signal in a self-defined coding mode to obtain a time coding signal with the frequency of 10Hz and the code element length of 10 whole periods;
synthesizing the time coding signal and the voice signal to be modulated of the radio station by adopting a signal synthesizer to obtain a synthesized signal;
modulating the synthesized signal to obtain a modulated synthesized signal, and sending the modulated synthesized signal to a receiving end through radio waves;
receiving end:
receiving the modulated and synthesized signal, and demodulating the modulated and synthesized signal by adopting a pair of orthogonal signals with the same frequency as the carrier frequency signal of the transmitting end to obtain a demodulated and synthesized signal, wherein the demodulated and synthesized signal comprises a demodulated time coding signal and an audio signal;
when a receiving end needs to normally receive a time signal, dividing the demodulated composite signal into two paths of signals, and inputting the first path of signal serving as an audio signal into an audio signal subsequent processing module; and filtering the second path of signals by adopting a 20Hz low-pass filter to obtain demodulated time coding signals, and decoding the demodulated time coding signals to obtain UTC time signals.
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Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4939789A (en) * | 1987-01-20 | 1990-07-03 | Matsushita Electric Industrial Co., Ltd. | Signal receiver for terrestrial and satellite broadcastings |
| JPH05249256A (en) * | 1991-12-31 | 1993-09-28 | Daewoo Electron Co Ltd | Receiver time automatically setting and/or correcting system and its method |
| JPH05328322A (en) * | 1992-05-27 | 1993-12-10 | Mitsubishi Electric Corp | Time using system |
| JPH0712963A (en) * | 1993-06-22 | 1995-01-17 | Sony Corp | Clock device |
| JPH09292478A (en) * | 1996-04-30 | 1997-11-11 | Casio Comput Co Ltd | Radio wave receiver |
| CN1711746A (en) * | 2002-11-07 | 2005-12-21 | 皇家飞利浦电子股份有限公司 | Mobile radio receiver with improved real-time precision |
| CN101620271A (en) * | 2008-06-30 | 2010-01-06 | 廖恒俊 | Method and system for locating a geographical position using broadcast frequency modulation signals |
| CN202257089U (en) * | 2011-09-28 | 2012-05-30 | 杭州科利特信息技术有限公司 | Time synchronization device |
| CN103095620A (en) * | 2013-01-21 | 2013-05-08 | 国家广播电影电视总局广播科学研究院 | Sending and receiving method and device of frequency modulation frequency range digital broadcasting signal |
| CN105071914A (en) * | 2015-07-27 | 2015-11-18 | 深圳思凯微电子有限公司 | Digital frequency modulation (FM) broadcast based clock synchronization method and FM broadcast receiver |
| CN106911415A (en) * | 2017-03-01 | 2017-06-30 | 中国科学院国家授时中心 | A kind of method that time service is realized in utilization FM frequency modulation broadcastings |
| CN107171761A (en) * | 2017-04-19 | 2017-09-15 | 西安电子科技大学 | The method that local clock is calibrated using shortwave time signal |
-
2021
- 2021-12-30 CN CN202111663436.5A patent/CN114326362B/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4939789A (en) * | 1987-01-20 | 1990-07-03 | Matsushita Electric Industrial Co., Ltd. | Signal receiver for terrestrial and satellite broadcastings |
| JPH05249256A (en) * | 1991-12-31 | 1993-09-28 | Daewoo Electron Co Ltd | Receiver time automatically setting and/or correcting system and its method |
| JPH05328322A (en) * | 1992-05-27 | 1993-12-10 | Mitsubishi Electric Corp | Time using system |
| JPH0712963A (en) * | 1993-06-22 | 1995-01-17 | Sony Corp | Clock device |
| JPH09292478A (en) * | 1996-04-30 | 1997-11-11 | Casio Comput Co Ltd | Radio wave receiver |
| CN1711746A (en) * | 2002-11-07 | 2005-12-21 | 皇家飞利浦电子股份有限公司 | Mobile radio receiver with improved real-time precision |
| CN101620271A (en) * | 2008-06-30 | 2010-01-06 | 廖恒俊 | Method and system for locating a geographical position using broadcast frequency modulation signals |
| CN202257089U (en) * | 2011-09-28 | 2012-05-30 | 杭州科利特信息技术有限公司 | Time synchronization device |
| CN103095620A (en) * | 2013-01-21 | 2013-05-08 | 国家广播电影电视总局广播科学研究院 | Sending and receiving method and device of frequency modulation frequency range digital broadcasting signal |
| CN105071914A (en) * | 2015-07-27 | 2015-11-18 | 深圳思凯微电子有限公司 | Digital frequency modulation (FM) broadcast based clock synchronization method and FM broadcast receiver |
| CN106911415A (en) * | 2017-03-01 | 2017-06-30 | 中国科学院国家授时中心 | A kind of method that time service is realized in utilization FM frequency modulation broadcastings |
| CN107171761A (en) * | 2017-04-19 | 2017-09-15 | 西安电子科技大学 | The method that local clock is calibrated using shortwave time signal |
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