TWI430586B - Signal transmitting device - Google Patents

Description

Signal transmitter

The present invention relates to a signal transmitting device, and more particularly to a signal transmission and device using a conductive housing.

Recently, due to the interaction between the energy crisis and the health trend, the bicycle industry has become one of the hottest industries. As a result, a wide variety of bicycles have been continuously developed, and the surrounding accessories have also become the target of competition among various manufacturers.

However, the safety of bicycles has become an inevitable demand after bicycles have become alternative vehicles. In order to increase the safety of the bicycle, various additional equipments have gradually been developed. For example, the Republic of China new patent No. M328996 "vehicle warning system" uses Zigbee technology and is used on the bicycle warning system to facilitate the installation of the warning system. The disadvantage is that the Zigbee device is expensive and not easily accepted by consumers. The simplest warning system is to use the traditional transmission line to control the warning signal, but the wired transmission will increase the complexity of the bicycle and is not easily accepted by the public.

For the architecture of the entire communication system, please refer to FIG. 1. The communication architecture 10 includes a signal transmitting device 20, a local oscillator 30, a communication channel 40, and a signal receiving device 50. In the communication system, if the input data inp is to be converted into an analog wave signal, the input signal must first be generated by the signal transmitting device 20 to generate a radio wave transmitting signal X, and transmitted to the communication channel 40, and the communication channel 40 is the medium between the transmitting end and the receiving end. The general communication channel has a wired channel or a wireless channel. The transmission signal passing through the communication channel 40 is distorted by the channel interference. When the signal receiving device captures the distorted reception signal VR, the signal receiving device generates the output data m when decoding. In the case of bicycles, for example, by means of wired or wireless means, the signals are transmitted through the transmission line or the air, so that the transmission data of the transmitting end is transmitted to the receiving end.

However, the modulation methods in the signal transmitting device 20 are most commonly used: analog and digital. If the modulation method is analogous, the three characteristics of amplitude, frequency and phase can be classified into amplitude modulation AM, frequency modulation FM and phase modulation PM. The analog modulation has a local oscillator, and the local oscillator is also a carrier signal. The carrier signal is modulated according to an input signal. If the amplitude is modulated by AM, the carrier signal is changed according to the amplitude of the input signal. The frequency modulation FM is the frequency of changing the carrier signal, and the phase modulation PM is the phase of changing the carrier signal.

If the signal is continuous, such as an analog signal that converts the sound, the modulation method used will be the analog modulation method mentioned in the previous two major themes. If the signal is digital, that is, continuous binary serial data, such as 110111 data, the modulation method will be different from the analog modulation. Next, the following describes some modulation methods of digital signals. Please refer to the ASK, FSK and PSK waveforms in Figure 2, where PCM is the input binary data 110111 to modulation transmission.

(1) Switch / (On-Off key, referred to as OOK)

The on key corresponds to 0 corresponding to 0,1 corresponding to Acos(2π f _c t), where A is a preset amplitude, cos(2π f _c t) is a cosine function, and f _c is the carrier frequency. Therefore, the transmitter only needs one oscillator and one switch gate.

(2) Frequency Shift Key (FSK)

The two-bit frequency shift key corresponds to 0 to Acos(2π f _c t), 1 corresponds to Acos(2π( f _c +Δ f )t), Δ f is the interval of one frequency, different receiving modes and frequency of signals The width will affect the minimum frequency interval for reliable transmission.

(3) Phase Shit Key (PSK)

The two-bit phase shift key corresponds to 0 to Asin(2π f _c t+θ), and 1 corresponds to Asin(2π f _c t-θ), where sin(2π f _c t) is a sine function and θ is a preset The phase, when θ is 90° and 270°, has the lowest error rate, also called the two-phase shift key.

However, warning systems or electronic devices on bicycles are not currently standard equipment like motorcycles. However, in the past, if the wireless method was used, it is a problem of power consumption. For example, the warning system and device on the bicycle use a battery, and the battery has a certain performance. If the wireless signal is used to design the signal transmitting device It will cause a large amount of power consumption of the battery on the signal transmitting device, so that the warning system and the device on the bicycle often replace the battery, causing inconvenience to the user. And if the transmitting system is wireless, it will cause the price to be too expensive and thus less popular. Therefore, how to develop a signal transmitting device with a lower price and lower power consumption will become a direction for the warning system or electronic device on the bicycle.

In view of the above problems of the prior art, the present invention provides a signal transmitting device using a conductive housing for transmitting electric waves, and the signal is modulated by OOK or FM modulation to achieve instant OOK or using a conductive housing. The purpose of FM signal transmission.

The object of the present invention is to provide a signal transmitting device. In addition, in the past, the wireless modulated transmitting device must consume a large amount of power, and the architecture of the present invention can save power consumption of the signal transmitting device.

Another object of the present invention is to provide an OOK modulation that utilizes the carrier frequency of the frequency generating unit to modulate the input data to convert the input data into digital OOK data.

It is still another object of the present invention to provide a transmitting unit that converts a plurality of square waves into a plurality of sine waves by using the principle of a resonant circuit, and transmits signals to the conductive housing by the coupling unit.

It is still another object of the present invention to provide an FM modulation that utilizes a carrier frequency of a frequency generating unit to modulate input data to transform input data into FM data.

The above and other objects, features and advantages of the present invention will become more apparent and understood.

It is an object of the present invention to develop a low-cost, low-power, signal-emitting device that can be applied to an electronic device having a conductive housing as a signal transmission medium. Taking a bicycle as an example: a transmitting signal device emits a transmitting signal having radio wave properties and can be applied to a bicycle frame having a conductive component. However, in addition to bicycles, for other conductive housings having conductive components, the present invention can also be used to make conductive housings as transmission lines, such as LED lamps, LED street lamps, locomotives, automobiles, home appliances, and the like having a conductive housing. The invention can be used to achieve wireless applications. In other words, the present invention utilizes a conductive housing that acts as a "wire", thus making the present invention a special technique for non-wireless and non-wireless transmission. The conductive housing may also contain any metal component such as gold, silver, copper, etc., and a conductive shell having a carbon fiber component may also be suitable.

The commonly used digital modulation system has OOK, FSK, PSK and other modulation methods, and in order to reduce the power consumption of the present invention, the OOK modulation method is adopted, which will make the power consumption of the signal transmitting device be more powerful than other modulation devices. Has lower power consumption. Since the modulation mode of OOK is that the transmission signal is 1, the modulation system is to adjust 1 to a plurality of sine waves, and when the transmission signal is 0, the modulation is to change 0 to not transmit any signal, thereby Save the power of the signal transmitting device.

Please refer to FIG. 3 , which is a signal transmitting and receiving system 200 for transmitting by using a conductive housing according to the present invention, comprising: a signal transmitting device 100 and a signal receiving device 320 . The signal transmitting apparatus 100 of the present invention includes a frequency generating unit 120, a modulation unit 110, a transmitting unit 130, and a coupling unit 180. The frequency generating unit 120 is configured to generate an operating frequency. The modulation unit 110 is connected to the frequency generating unit 120 for receiving the input data, and performing a switching modulation on the input data by using the operating frequency to generate the modulation signal. The transmitting unit 130 is connected to the modulation unit 110 for receiving the modulation signal and performing resonance amplification to generate a transmission signal. The coupling unit 180 in the signal transmitting device 200 is coupled to the modulation unit 110 for loading the transmitting signal to the conductive housing 210. The conductive housing 210 can be a self-conducting housing, and can also be a device having a conductive housing 210, such as an automobile or a household electrical appliance. The conductive housing may also contain any metal component such as gold, silver, copper, etc., and the conductive shell having the carbon fiber component may also be used, and may also be a general power cord.

The signal receiving device 320 includes a coupling unit 310, a resonance unit 320, and a demodulation unit 330. The coupling unit 310 in the signal receiving device 320 receives the transmission signal generated by the signal transmitting device 100 via the conductive housing 210. The resonant unit 320 is coupled to the coupling unit 310, and the transmitting signal is transmitted to the resonant unit 320 through the coupling unit 310. At this time, the resonant unit 320 performs resonance filtering to generate a resonant signal, and transmits the signal to the demodulation unit 330 for demodulation. Output data.

Next, please refer to FIG. 4, which illustrates a waveform diagram of the entire signal transmission process of the OOK modulation method of the present invention. First, the input data inpdata received by the modulation unit 110 in FIG. 4, the input data inpdata is a continuous number of binary sequences, for example, the number of binary sequences of 110111. After the modulation unit 110 receives the input data inpdata, the frequency generating unit 120 is connected to the modulation unit 110, and the modulation unit 110 performs signal modulation on the input data inpdata according to the frequency signal generated by the frequency generating unit 120 to generate the modulation signal M. . According to the concept of the communication system, the number of the 10111 binary sequence is the baseband data, and the frequency generated by the frequency generating unit 120 is the frequency of the carrier. When the data of the fundamental frequency is multiplied by the carrier frequency , the modulation signal M is generated, please refer to the modulation signal M in Fig. 4.

The frequency generating unit 120 can adopt a LC oscillator, a Voltage controlled oscillator (VCO), a crystal, etc., and the modulation frequency range of the OOK can be 40k to 15MHz. between.

Then, the modulated signal M is transmitted to the transmitting unit 130 for resonance signal amplification to generate a transmission signal. The transmitting unit 130 is a resonant circuit. When the modulated signal M is input to the one-wave signal, the resonant circuit generates a sinusoidal signal. That is, when the modulation signal M is a multi-wave signal, the resonant circuit generates a plurality of sinusoidal signals. Then, the transmission signal is transmitted to the coupling unit by radio waves. The coupling unit 180 and the conductive housing 210 form a capacitive coupling body, the transmitting signal passes through the coupling unit 180 in an electric wave manner, and the coupling unit 310 transmitted to the receiving end via the conductive housing 210 receives the signal VR. At this time, the reception signal VR received by the resonance unit 320 in the signal receiving device 300. The receiving signal VR received by the resonant unit 320 is received by the resonant principle and is received as a resonant signal R. The so-called resonant principle is also a band pass filter. Only when the received signal VR belongs to the frequency band of the filter, the resonant unit 320 can Receiving this received signal VR. Demodulation unit 330 will then demodulate the resonant signal R to restore the input data. Finally, the output data outdata output is the input data inpdata. Wherein, since the transmitting signal passing through the conductive housing 210 is attenuated and external noise is fed into the conductive housing. Therefore, the resonating unit 320 in the signal receiving device 300 must need to set a better band pass filter to filter the transmitted signals transmitted from the coupling unit 310 to filter out unnecessary noise.

The coupling unit 180 can have only one coupling capacitor or a plurality of coupling capacitors, and the coupling capacitor can be formed by using a single piece of metal as one side of the capacitor and the conductive portion of the conductive housing 210 as the other side of the capacitor. That is, the coupling capacitor can be a single piece of metal and then coated with an insulating layer to form a capacitor when it contacts the conductive housing 210. This capacitor can be considered as a coupling capacitor. Taking a bicycle as an example, if it is to be mounted on the handle, the aforementioned single piece of metal piece can be made into an annular elastic structure to be fixed on the metal body of the handle. The insulating layer may also be painted on the body of the bicycle casing, and the insulating layer is added as a medium, and the medium to be transported is not affected.

Next, please refer to FIG. 5, which illustrates a functional block diagram of the transmitting unit 130 of the present invention. The transmitting unit 130 includes a first buffer 140, a second buffer 150, a resonant capacitor 144, and a resonant inductor 142. The first buffer 140 is connected to the modulation unit 110 for receiving the modulation signal and performing current driving to generate the first buffer signal. The second buffer 150 is connected to the modulation unit 110 for receiving the modulation signal and performing current driving to generate a second buffer signal. The resonant capacitor 144 has a capacitive impedance, and the first end of the resonant capacitor 144 is coupled to the second buffer 150. The resonant inductor 142 has an inductive impedance. The first end of the resonant inductor 142 is coupled to the first buffer 140, and the second end of the resonant inductor 142 is coupled to the second end of the resonant capacitor 144. After the first buffer 140 and the second buffer 150 receive the modulated signal, the first buffer is formed because the capacitive impedance of the resonant capacitor 144 forms a series resonant circuit with the inductive impedance of the resonant inductor 142. The 140 generates a current signal to the second buffer 150, and generates a transmission signal at a connection point between the second end of the resonant capacitor 144 and the second end of the resonant inductor 142.

The transmitting unit 130 is a resonant circuit composed of a series resonant circuit. When the modulated signal M is input into a one-wave signal, the resonant circuit generates a sinusoidal signal. The first buffer 140 and the second buffer 150 are combined into a push-pull amplifier. In addition to eliminating harmonic distortion, the push-pull amplifier can further change the current flowing from the first buffer 140 to the second buffer 150. high. After the square wave signal is sent to the transmitting unit 130, the first buffer 140 is a positive voltage Vb1, and the second buffer 150 is a negative voltage Vb2, so that the current flowing from the positive voltage to the negative voltage is lower than the positive voltage and the negative voltage. The structure's current is increased by a factor of two to enhance the driving force of the current.

Next, please refer to FIG. 6, which illustrates a description of the operation of the resonant circuit of the transmitting unit 130 of the present invention. The resistance of the equivalent resistance Rth is determined by the line resistance, and the resonant inductor 142 has an inductance resistance value XL, and the resonant capacitor 144 has a capacitance blocking value XC. Therefore, the total impedance Z of the circuit is equal to the equivalent resistance plus the resonant inductor 142 plus the resonant capacitor 144. Since the inductance impedance value XL has a phase difference, if the current is used as a reference, it represents a voltage leading phase current of 90 degrees, so multiply the sign of positive j, the same capacitance impedance value XC also has a phase difference, if based on current, It represents a 90-degree phase angle of the voltage behind current, so multiply the sign of negative j, the total impedance of the circuit is Z=Rth+jXL-jXC. Where XL = 2π fL , f is the frequency of the input square wave, and L is the inductance value, and And f is also the frequency of the input square wave, and C is the capacitance value.

Moreover, when the circuit conforms to the resonant circuit, the representative XL is equal to XC, so Z will be equal to Rth. At this time, the first buffer 140 is a positive voltage Vb1, and the second buffer 150 is a negative voltage Vb2, wherein the positive voltage Vb1 It is the same size as the negative voltage Vb2 and the voltage is opposite. Its equivalent voltage Vth is equal to the positive voltage Vb1 minus the negative voltage Vb2 such that Vth = 2Vb1. At this time, the equivalent current Ith is the equivalent voltage Vth divided by Rth, that is, the formula is Ith=Vth/Z, and the maximum current is obtained. And since the circuit is a resonant circuit, the output end of the transmitting unit 130 measures the sine wave of the positive half cycle of the transmitting signal X, and when the current stops, the sine wave of the negative half cycle is generated, so when the square wave signal is input once To the transmitting unit 130, the transmitting signal output by the transmitting unit 130 generates a complete sine wave, and when a plurality of square wave signals are input, a plurality of sine waves are generated.

Wherein, since the size of the transmitted signal X measured by the output end of the transmitting unit 130 is related to the quality factor of the circuit, the definition of the quality factor is related to the prior art familiar to those familiar with circuit science, and will not be described herein. Therefore, the voltage V at both ends of the resonant capacitor 144 is equal to the quality factor multiplied by the equivalent voltage (Vc = Q * Vth). That is, the voltage at one end of the resonant capacitor 144 is the end point of the ground, that is, the output end of the transmitting unit 130, and the generated signal is also the size of the transmitted signal X. It can be clearly seen from FIG. 4 that when the modulation signal M inputs a continuous square wave signal to the transmitting unit 130, the size of the transmitting signal X measured by the output end of the transmitting unit 130 can be transmitted by the fourth picture. Signal X knows that the signal is amplified. The transmitted signal X is a sinusoidal wave having radio wave properties, and the sinusoidal wave of the radio wave property can be transmitted to the conductive casing in a radiation manner via the coupling unit. Please note that the sinusoidal wave of this radio wave nature does not have the ability to drive the load, and cannot directly drive the load, but radiates the conductive housing through the coupling unit 180.

Next, the meaning of the resonant frequency and bandwidth of the present invention will be explained below, wherein the resonant frequency L represents the inductance value of the resonant inductor 142, and C represents the capacitance value of the resonant inductor 142. The bandwidth of the transmitting unit 130 of the present invention is equal to the resonant frequency divided by the quality factor ( The carrier frequency of the transmitted signal is the carrier frequency of the OOK in the present invention between 40 kHz and 15 MHz, that is, the carrier frequency does not exceed the frequency of the resonant frequency. The carrier frequency is based on the operating frequency generated by the frequency generating unit 120, that is, the operating frequency is between 40 kHz and 500 kHz.

Furthermore, the architecture of the present invention can also be applied to FM modulation systems. Next, please refer to FIG. 7 to illustrate the waveform diagram of the entire signal transmission process of the present invention using the FM modulation method. First, the input data in FIG. 7 is input to the modulation unit 110, and the input data inpdata is a continuous number of binary sequences, for example, the number of binary sequences of 110111. After the modulation unit 110 receives the input data inpdata, the frequency generating unit 120 is connected to the modulation unit 110, and the modulation unit 110 performs signal modulation on the input data inpdata according to the frequency signal generated by the frequency generating unit 120 to generate the modulation signal M. . In the FM modulation system, the FM modulation method is used, when the 1 data is transmitted, the carrier wave of f1 is transmitted, and when the 0 data is transmitted, the carrier wave of f2 is transmitted, and the frequency generating unit 120 is also To adjust different carrier frequencies. The frequency generating unit 120 can adopt a voltage controlled oscillator (VCO), a crystal, etc., and the modulation frequency range of the application FM can be between 400k and 15MHz.

Then, the modulated signal M is transmitted to the transmitting unit 130 for resonance signal amplification to generate a transmission signal. The transmitting unit 130 is a resonant circuit. When the modulated signal M inputs different square wave signals, the resonant circuit also generates different sinusoidal signals. That is, when the modulation signal M is a different square wave signal, the resonant circuit generates different sinusoidal signals. Then, the transmission signal is transmitted to the coupling unit by radio waves. The coupling unit 180 and the conductive housing 210 form a capacitive coupling body, the transmitting signal passes through the coupling unit 180 in an electric wave manner, and the coupling unit 310 transmitted to the receiving end via the conductive housing 210 receives the signal VR. At this time, the reception signal VR received by the resonance unit 320 in the signal receiving device 300. The receiving signal VR received by the resonant unit 320 is received by the resonant principle and is received as a resonant signal R. The so-called resonant principle is also a band pass filter. Only when the received signal VR belongs to the frequency band of the filter, the resonant unit 320 can Receiving this received signal VR. The demodulation unit 330 then performs FM demodulation on the resonant signal R to restore the input data. Finally, the output data outdata output is the input data inpdata. Wherein, since the transmitting signal passing through the conductive housing 210 is attenuated and external noise is fed into the conductive housing. Therefore, the resonating unit 320 in the signal receiving device 300 must need to set a better band pass filter to filter the transmitted signals transmitted from the coupling unit 310 to filter out unnecessary noise.

Therefore, with the present invention, it is possible to develop a signal transmitting device which is lower in price and consumes less power. In order to make the signal emission reach a very low power consumption, the modulation mode used in the present invention adopts the OOK/FM modulation mode. If the OOK modulation mode is adopted, only the radio wave is transmitted when the data is transmitted. When transmitting 0 data, no radio waves can be transmitted. In the FM modulation mode, when 1 data is transmitted, the carrier wave of f1 is transmitted, and when 0 data is transmitted, the carrier wave of f2 is transmitted. Therefore, in order to achieve the modulation mode of OOK or FM, the present invention designs a transmitting circuit in the transmitting unit 130 by means of R, L, C series resonance. Therefore, the use of the present invention can indeed reduce the cost and reduce the cost of the signal transmitting device.

While the preferred embodiment of the invention has been described above, it is not intended to limit the invention, and it is obvious to those skilled in the art that the invention may be modified and modified without departing from the spirit and scope of the invention. The patent protection scope of the invention is subject to the definition of the scope of the patent application attached to the specification.

10. . . Bicycle frame

20. . . Signal transmitter

30. . . Local oscillator

40. . . Communication channel

50. . . Signal receiving device

100. . . Signal transmitter

110. . . Modulation unit

120. . . Frequency generating unit

130. . . Launch unit

140. . . First buffer

142. . . Resonant inductor

144. . . Resonant capacitor

150. . . Second buffer

180. . . Coupling unit

200. . . Signal transmitting and receiving system

210. . . Conductive housing

310. . . Coupling unit

300. . . Signal receiving device

320. . . Resonant unit

330. . . Demodulation unit

Figure 1 is a sample design of a bicycle; (prior art)

Figure 2 is the communication signal modulation map; (previous technology)

Figure 3 is a system of the signal transmitting and receiving system of the present invention;

Figure 4 is a modulation diagram of the OOK signal of the signal transmitting and receiving system of the present invention;

Figure 5 is a functional block diagram of the transmitting unit of the present invention;

Figure 6 is a detailed explanatory diagram of a resonant circuit of the transmitting unit of the present invention; and

Figure 7 is a modulation diagram of the FM signal of the signal transmitting and receiving system of the present invention.

100. . . Signal transmitter

110. . . Modulation unit

120. . . Frequency generating unit

130. . . Launch unit

180. . . Coupling unit

200. . . Signal transmitting and receiving system

210. . . Conductive housing

310. . . Coupling unit

300. . . Signal receiving device

320. . . Resonant unit

330. . . Demodulation unit

Claims (4)

A signal transmitting device is applied to a conductive housing, the device comprising: a frequency generating unit for generating an operating frequency; a modulation unit coupled to the frequency generating unit, receiving an input data, and applying the operating frequency to the The input data is modulated to generate a modulation signal; a transmitting unit is connected to the modulation unit, receives the modulation signal and performs resonance amplification to generate a transmission signal, and the transmitting unit comprises: a first buffer, Connecting the modulation unit, receiving the modulation signal and performing current driving to generate a first buffer signal; a second buffer connected to the modulation unit, receiving the modulation signal and performing current driving to generate a second buffer a resonant capacitor having a capacitive impedance, a first end of the resonant capacitor being coupled to the second buffer; and a resonant inductor having an inductive impedance, the first end of the resonant inductor being coupled to the first a buffer, and a second end of the resonant inductor is connected to the second end of the resonant capacitor and the coupling unit; wherein, when the first buffer is After the second buffer receives the modulation signal, the capacitor impedance of the resonant capacitor forms a series resonant circuit with the inductance of the resonant inductor, so that the current of the first buffer signal of the first buffer flows to the first The second buffer signal of the second buffer, and the second end of the resonant capacitor and the second end of the resonant inductor generate the transmit signal to the coupling unit, connected to the modulation unit, and receive the modulation Signaling and performing resonant amplification to generate a transmitted signal; The transmitting unit has an equivalent impedance, the equivalent impedance, the capacitive impedance, and the impedance of the inductor form a series resonance. When the capacitive impedance is equal to the impedance of the inductor, the current signal stream is generated to flow from the first buffer to the second buffer. Wherein the equivalent impedance, the impedance of the capacitor forms a series resonance with the impedance of the inductor to generate a quality factor, the voltage value of the transmitted signal is the quality factor multiplied by the voltage of the modulated signal; and a coupling unit, The transmitting unit and the conductive housing are coupled, and the transmitting unit loads the transmitting signal to the conductive housing via the coupling unit. The device of claim 1, wherein the first buffer and the second buffer are combined into a push-pull amplifier to increase the transmitted signal output strength. The device of claim 1, wherein the modulation unit performs signal modulation by a frequency modulation or a switching modulation. The apparatus of claim 1, wherein the operating frequency ranges from 40 kHz to 15 MHz.