TWI244314B - Wireless modem - Google Patents

Abstract

A modem includes a base unit for transmitting a data signal, and a communication card which receives the data signal from the base unit over a wireless medium and which performs echo canceling on the data signal. The base unit is in communication with a telephone line and receives an original signal from the telephone line. The base unit generates an RF modulated signal based on the original signal. The base unit includes a transmitter for transmitting the data signal. Circuitry in the base unit receives the original signal from the telephone line and generates a combined data signal from the original signal and echo signals and maintains a peak voltage excursion of the combined signal which is within the linear amplification region of the transmitter.

Description

2443l4. Description of the invention: [Technical field to which the invention belongs] The present invention relates to a wireless modem [Prior technology] Traditionally, computers are connected through a network system with a network. In this article, I will connect such as Internet telephone lines, Ethernet cables and similar multi-wires "-the word refers to such as Qi Qi < other wired links and so on. 10 Wired Pei Zhi has its limitations in use. It can be carried in 彳 ± t ^ ^ system. For example, wired devices have a life limit, because their operation is based on the connection of Zhongzhuang + m ′ line. There is also a limitation when wired installation is broken, because there are lightning nearby ^ _ u The wired device needs to be connected to a 4 socket or network socket. [Summary of the Invention] According to a feature of the present invention, the data machine of the present invention includes a 2 order ^ to send a data signal without non-linear distortion, and a communication card to receive this data wirelessly from a near-end unit. σ then performs the echo cancellation of this data signal. This feature may also include one or more of the following features. The near-end unit is used to communicate with the telephone line and receive from the phone line. "The tiger near-end unit generates an RF modulation based on the original signal. The near-end unit contains a transmitter to send data signals, and a =: system to The circuit receives the original signal from the telephone line, and this circuit keeps its peak voltage deviation (exeursiGn) by combining the original and echo signals within the linear amplification range of this transmitter's 1244314 to generate data from the original signal: Signal. This circuit system in the near-end unit can be an automatic gain control circuit. This data signal can be sent using Multi-level Frequency Shift Keying or FSK ^ W #. Near-end unit Sending data signals in the channel of wireless media. Generally speaking, the present invention is a data machine, which includes a single-end single heart card to send data signals to the near-end ... and receive data signals from the near-end 10 This communication card is self-contained. Λ 卞 includes a switch to select 杲 a media form, and on the basin, /, on the hairpin and receive data signals. The media form can be $, ^ ^ ^ t, line, and circuit system can be included in the ^ Λ card. This circuit is a white test circuit. The circuit is equipped with a wired presentation indicator, which can be detected by a wired medium. When &## A $ # is detected, after:: Off (or a switch). The trigger switch operates the modem in some cases. When the wired presentation indicator does not detect the wired carcass, the 'switch is triggered to operate the modem in wireless mode. According to another feature of the present invention, the near-color 'modem of the present invention includes: 20 ^.及; and a communication card, which passes through the line A to the telephone line, and from the telephone line,% includes a hook switch, which precisely draws DC current from the telephone central office mine with a thunder battery. And occupy the q € phone line to provide a Lei Ye to give instructions. l ,,,, and 6 of the data signal that has been prepared to send data. l2443l4 Other features and advantages of the present invention will be shown by the following description, including the scope of the claimed patents and illustrations. [Embodiment] 5. In order to allow your review committee to better understand the technical aspects of the present invention, various preferred specific embodiments are described below. Figure 1 shows a wireless modem. The wireless modem includes a near-end unit 11 and a wireless modem card 12 (or 19). The wireless modem card 12 is connected to a computer 13. The wireless modem card 12 may be a PCMCIA (Personal Computer Memory Card International Association) 'also known as a PC card for a laptop 10 computer, and may be a PCI / mini for a desktop computer (pc) -PCI (peripheral parts connection interface) card, or other interfaces to other computing devices such as USB. The near-end unit 11 is inserted into a telephone 15 wall socket 15 through a two-core telephone line 14 and connected to the public telephone network "^ ...". The communication between the near-end unit 11 and the wireless modem card 2 (ie data Switching) is performed via a radio frequency (RF) link 16. The radio frequency link 16 sends a standard telephone spectrum, also known as the "voice band" frequency, which extends from 50HZ to 4kHz (仟 Hz). Therefore, Note 20 audio band modem signals can be transmitted in the wireless (radio wave) channel. The modem signal can be operated according to the latest dial-up connection international standards (ITU), such as ν · 34 and ν · 90, to provide a data transmission rate of up to 56 仟 bits per second (kb / s). The range of the RF link can vary, but is usually a few hundred feet or longer. 7 1244314 As described below, 'Wireless modem 10' can also be operated in an 'a mode. In this wired mode,' Wireless modem 10 'uses a telephone line to be placed on the telephone wall socket 15. The information is sent on the phone. Instead of sending on the RF link 16, nearly 5 yuan 11 is not needed in this example. The near-end unit Figure 2 is a block diagram of the near-end unit 11, the near-end unit includes the telephone line interface 20, and the telephone line. Interface 20 is also called data storage 10 (DAA). It is combined with near-element 11 through flexible cord 14 and socket 15 to make it a standard two-core, twisted-pair telephone line. fltip ”and” ring ”) line. Figure 3 shows the circuit system of the telephone line interface 20. This telephone combines the near-end unit 11 and the telephone line, so it can be connected to the equipment in the telephone 15. This circuit system Includes electronic bell detector 22, voltage protection circuit 23, bridge rectifier and loop DC circuit 24, and hook switch circuit 25. Electronic bell detector 22 receives and responds to the bell signal sent from the phone to the near-end unit. The ring signal indicates that 2 The connection to the wireless modem has been established. Acoustic L is a high-voltage, low-frequency signal, 90 Vrms (average voltage), and 15 to 68 Hz (hertz) are typical signals. (Shown) can limit the signal voltage to less than 1 2 V, which can trigger the electronic bell detector 22. "Line ~ beam line on the line contains a single pick-up of the end-of-line orders often received by the Central Bureau of the Central Government, the overholding of the Central Bureau has one Suzuki's roots make its 1244314 overvoltage protection circuit 23 protect against high voltages conducted by telephone lines, such as high voltage caused by lightning or other phenomena. Overvoltage protection circuit 23 is used in this embodiment. Zener diodes and variable resistors are built in. 5 Bridge rectifier circuit 24 protects against improper voltage polarity on both ends of the telephone line, such as incorrect telephone line connection or changing the battery's positive polarity in the central telephone office. Negative pole, etc. This protection circuit 24 is constructed by a full-wave rectifier using four diodes. The related rectus electrical circuit maintenance circuit 24 maintains this dc current at the phone line at a relatively fixed level of 10, such as 25 m A (milliampere), its current level depends on the length of the telephone line. In order to integrate the circuit system, the transformer 29 provides additional isolation from the telephone line in the near-end unit 11. The hook switch circuit 25 connects to the near-end unit 丨丨 To the telephone line, the hook switch circuit 25 occupies the telephone line by drawing a direct current (dc) 15 from the telephone central office battery, thereby indicating that the telephone central office has entered the off-hook state. With the telephone connected, it can enter the state that can send and receive signals, just as the telephone receiver enters the "hook off" shape L. The DC current can be different, from 20mA to 120mA according to the length of the electric line to the telephone central office. The hook switch circuit 25 can be constructed using a signal solid state relay or an optical coupler. The wired presence indicator 27 (also shown in Fig. 3) does not appear in the near-end unit 11. In practice, it can be implemented in the DC maintenance circuit 24 of the circuit. As long as a telephone is used, the DC current 9 1244314 flows through the DC maintenance circuit 24 of the circuit. description of. Returning to Figure 2, the near-end, ^ ^ ^ ^ A (缟 Early Wu 11 also contains a composite circuit 30, automatic gain control circuit Λ ^ (AGC) 31, radio transmitter 32, microprocessor 33, radio receiver The device processor is 35, and the antenna 36. The microprocessor 33 controls the work of the near-end unit by talking with the telephone line interface 20, the radio transmitter 32 and the radio receiver 34.

can. The microprocessor 33 also transmits and receives control signals to and from the benefit line modem card 12. 10 The radio transmitter 32 translates the data signal of the voice band from the telephone line 14 into a modulated radio frequency signal. The radio receiver 34 translates the modulated radio frequency signal into a voice band data signal. The radio transmitter 32 and the radio receiver 34 operate at different frequencies, but both are connected to the same antenna 36 by using a duplexer 35. The radio frequency signal is transmitted to the wireless modem card 2 via the 15 antenna 36 and received by the wireless modem card 12.

The RF signal can be modulated by the radio transmitter 32 using different technologies. The modulation range is from analog FM (frequency modulation) to digital FM, such as frequency shift keying (FSK) and digital spread spectrum technology. 20 The choice of FM method is largely dominated by the characteristics of the speech and audio data signals. For example, the signal V. 34 has a complex multi-state quadrature amplitude modulation (QAM) composition and an analog baseband signal similar to a 4KHz telephone channel for transmission. The V.90 signal is composed of a Pulse Amplitude Modulation (PAM) signal in 128 discontinuous amplitude planes. 10 1244314 is based on the micron rule used in digital public tensioners (―XP1: Road (PSTN) to expand xPander). To distinguish. 5 15 20 High-line: ϊ Ϊ: The accurate transmission of the signal of the machine is required-low noise and the above-mentioned methods and channels are used for transmission '-a transmission according to this invention with V · 34 or V · 9. The signal ⑽ ^ ° ”is transmitted through the RF channel. Ν · 9〇

The two I / this transmission method is actually similar to the transmission — a frequency shift button method with 128 distances (FSK Frequeney Shm) It seems that this radio frequency needs 3 () khz to transmit this message, this method type ^; general wireless telephone Use in analog FM channel bandwidth. If the bandwidth is increased, the noise ratio may increase.

The preferred method here is to use analog FM modulation. One is the method widely used by radiotelephones of 900MHz or other frequencies (as mentioned above, taking the V · 90 signal as an example, this modulation method is equivalent to Equal space level frequency shift key method). Analog modulation avoids the quantization noise problems of digital radio frequency, analog-to-digital, and digital-to-analog conversion. These conversions will reduce the v.90 signal quality and also avoid the need for higher bandwidth (eg 200KHz) in digital RF (compared to only 30kHz on analog FM channels). For frequency modulation, the ν · 90 signal is used directly in one of the frequency modulation deflectors in the radio frequency converter 32. Technically this FM bias circuit is easier to meet the high linearity requirement of V · 90. If necessary, non-linear distortion can be further reduced by adding circuits to the FM deflector to limit or reduce signal amplitude. Usually 11 1244314 the FM channel is very stable, and its fundamental frequency gain is basically the same as the size of the Yang language (decay). The composite circuit 30 contains the anti :: effect. (5)) to convert the two-core i-four-core operation circuit and the operational amplifier (the function of the figure 30 is for the opposite two-way gate and the body, the composite circuit works), and make them open in one door Two signals (called full-duplex and inefficient operation from the slave-terminal (four lines) are shown on the composite terminal ⑴ and output; = = No. display machine Η2 goes through the composite circuit 3. Output. "号 疋 由The composite terminal 10 15 20 is because the composite circuit 30 is-the bridge electric number can only be used to synthesize the bridge's beautiful separated signal when there is a considerable mismatch. The result is: the signal will be partially reflected to the terminal 1 12 _? Sound ~ Office to the machine. This reflected wave will be amplified by two = signal 1 10, for example, and several times. For example 4, the main signal will be amplified by this = No. (including Echo) may cause a load of .32 and non-linear distortion. Several echoes 101 'cause the loss of non-linear distortion. ° Distortion caused by the data circuit 41 in the computer 3 cannot effectively reduce the load and non-linear distortion. Invented an AGC between the two-wire electrical transmitter 32 of the composite circuit 3 31. The circuit road 31 coffee inclusion - peak amplitude detector, having - a long, the mixed signal to the peak holding time fixed 1〇2 located 121244314 ::

The radio transmitter 32 is within a linear amplification range. Due to the low nonlinear distortion of the AGC circuit 3, the RF link M becomes substantially smaller in the data signal of the modem. Therefore, the echo canceller in the modem circuit 41 can completely eliminate the echo. In this case, the echo will occur on the composite circuit terminal 1 丨 丨. . The AGC circuit 31 also ensures that the signal on the terminal OM2 does not drop to a very low value. This function prevents a low signal amplitude from causing a low signal-to-noise conversion ratio on the radio frequency channel used for transmission, very far from the central office. ίο 15 20

Compared with the application of the AGC circuit at the intermediate frequency (IF), the linearity requirements of the AGC circuit 31 operating at the fundamental frequency become very strict. The solution is to use a special linear connection device with a gain that can be used to change the control voltage, or use a resistance step attenuation controller controlled by digital commands.

The gain control may be directly or through feedback. The direct control includes measuring an incoming voltage 101 and adjusting the voltage gain to achieve a stable output signal 102. On the other hand, the feedback control includes measuring the output 102 and maintaining the signal stability through the adjustment of the gain or reducer. One of the purposes of the AGC application is to obtain a fixed gain (or attenuation) setting to optimize the data channel under normal operation. However, because of the V.34 and V.90 data system handshake, the AGC program becomes very complicated. This is because the start program contains several states that last for several seconds, and the signal that changes the amplitude can be transmitted in both directions. This procedure requires the system's gain to be fixed and hold 13 1244314. The transmission of future data. because

Iugo V.34 and V.90 systems require the gain of circuit 31 to be set at the first starting%. We also use the following methods to achieve this effect. One method is to measure the level of the dial tone sent from the central office of the telephone company. This dial tone is the first message received ^ and the standards body has its clear marking specifications. The dial dial averages, and the data message sent also has a relationship with μ. Therefore, the broadcast tone is allowed to = the gain setting of the circuit 3 (forward or feedback control) to generate a ίο 15

The voltage is 102, so that the subsequent data transmission can be nearly optimized. The dB relationship between the dial tone standard and the voltage, 02, can be determined through experiments using a typical echo state in the loop. If there is a severe echo, a low voltage of 102 is required to prevent it in the RF channel. The non-linear distortion increased during transmission. These can increase the value of χ by one dB and one dB to achieve the required value. The second way is to measure the DC current sent from the central office, and then from this data Set the level of AGC. This method can be established because

The DC current can be used to accurately measure the loss from the central office to the subscriber. Imperfect echo cancellation, thermal noise (poor signal-to-noise conversion ratio of 20), and interference are all sources of transmission errors. This caused the modem circuit 4 丨 to return to half-duplex operation, reducing the data transmission speed (below 56Kb / s) and initiating a request to retransmit the data signal. Just as it is used in radiotelephones, security features can also be provided by the near-end unit Η. For example, to prevent unauthorized aerial interception of this near-end unit 14 1244314, a security code can be used, which can have 65,000,000 to one million different security codes (also known as "keys"), which can be The user randomly selects one. FIG. 4 shows a block diagram of a wireless modem card 12. The wireless modem card 12 includes a wireless modem interface 40 and a modem circuit 41. The modem circuit 41 is shown in FIG. 5 and includes an encoder / decoder (codec) 42, a digital signal processor (DSP) 43, a controller 44 and its associated memory, and a Computer interface 45. The codec 42 receives an analog voice band data signal from the wireless modem interface 40 (in the RF link 10 16), and receives a data signal from the DSP 43. The codec 42 includes: an A / D converter 46 to convert the input data signal (from the near-end unit) from an analog to a digital form; a D / A converter 47 to convert the output data signal (send To the near-end unit 1 2) from digital to analog form. 15 DSP 43 performs pulse amplitude modulation (PAM) on V.90 or quadrature amplitude modulation (Q AM) on V.34, echo cancellation of input data signals, and modulation of output signals by PAM or QAM. The DSP 43 also generates and detects DTMF (Dual Tone Multi Frequency) push-button dial signals. This push-button dial signal is used to connect to a remote network device. The 20 PAM routine is executed in DSP43 and uses a 128 level value, while the QAM routine is executed in DSP43 using more than one thousand QAM states. Each cancellation routine executed on DSP 43 typically includes a 128-tap delay line, which has a tap weight value set by the training sequence, and performs this weight setting before the data transfer begins. 15 1244314 10 15 20 ^ The controller 44 performs the control required by the wireless modem 10. These may include fax transmission and reception functions. For example, the controller 44 sends a hook command to the remote computer 13 by sending a hook command: it turns on the wireless data transmitters in sequence. Then the wireless modem interface 40 selects other devices used in the vicinity, and sends ^ skin near-end unit 'to the near-end unit 11 and wireless modem card 2' to ',,, and line connection 16'.凊 Note that this call origination procedure from computer i 3 'enables the transmitter of the wireless modem interface, as in the case of a telephone handset. In the ordinary wireless telephone, when this ON (or PHONE) switch on the 话筒 microphone is started, it turns on a series of actions to enable the wireless microphone to establish a wireless connection with its near end. Please note that it is exhausted until ^ 7 "丨 The reception of this wireless modem is turned on so as to receive any incoming phone calls. In this book, we use the wireless telephone # I 月 气 甘双立 Knowledge early 11 sets The same mechanism used when the wireless connection of the helmet modem card 12 to the "1" and "2" lines means that all standard radio masters are made by her own.

Here. The result is to use the hook switch 25 # μ of the line interface 20 to turn on the phone. The wireless modem + ^ ^ ^ is turned on. 12. The air path (airpathk 丄 and n) is transmitted through the near-end unit. i6 to receive a dial tone from Lei Shishi Central Office. At this point, the control of Lingzhong modem circuit 4 1 cries 44 recognizes the dialing sound, no cutting state ^ The wire modem is now ready for Miao, under the control of computer 1 3, dial the Guye dial modem Circuit 41 produces

Key tones signal to start dialing ^ MF 16 1244314 Because the key tones DMTF signal resides in the voice band, it is carried on the air path 16 to reach the near-end unit 11 and enters the telephone central office. Please note that unlike the wireless phone, the wireless modem card 1 2 • wireless modem interface 40 and the near-end unit 1 15 telephone line microprocessor 33 do not generate DMTF signals. All dialing functions are Generated by the computer 1 3, including the hook switch control 54 ° The controller 44 receives and approves the ring indication 6 1 from the near-end unit 1 1 the ring detector 2 2 via the microprocessor 5 3, and 10 pairs The incoming phone call responds and begins the hook operation. Another function of the controller 44 is that when the computer 13 requests the modem to stop working, the near-end unit 11 sends a start hook signal 5 4 to the hook switch 2 5 to stop the work. The computer interface 4 5 combines the modem circuit 4 1 to the computer 1 3. The data is transmitted on the computer interface 45 between the computer 13 and the wireless modem card 12. The computer interface 45 may be a standard PCMCIA connection of a portable computer, or a PCI connection of a desktop PC, or any other connection interface. Returning to FIG. 4, the wireless modem interface 40 includes an antenna 20 3 7, a duplexer 50, a radio receiver 51, a radio transmitter 52, and a microprocessor 53. The operation of these circuits is similar to the operation of the relative circuit system in FIG. 2 described above, that is, these circuits are used to exchange data with the near-end unit 11 17 1244314, so that when the wireless modem card 12 sends data, Nearly yuan 1 1 was able to receive this information and vice versa. The wireless modem card 12 communicates with the near-end I 1 on the radio frequency link 16. When the near-end unit 11 receives a call, the wireless 5 card 12 receives a ring indication from the near-end unit 11. The ringtone detection circuit 22 of the DAA 20 in the near-end II detects an acoustic signal and sends this information to the wireless modem card 1 2. In a normal radiotelephone application, this logic form starts a ringer oscillator and its associated voltage buzzer. 10 The signal in this logical form is not usually a modem circuit. 4 1 is possible, especially for the RING IN pin of the input controller 44 and Figure 6). This kind of information is therefore configured as a modem phase in the ringtone simulator 62.容 的 信号 6 1。 Content of the signal 6 1. From the data mechatronics, the bell indication signal is sent to the computer 1 3, where 15 is the input fax to send, or a request is made from the remote to brain 13 1 such as from the office location to the computer 1 3, 1 3 The incoming call will be recognized and a hook-off instruction will be initiated to establish an incoming call. As mentioned above, after receiving the ringtone detection signal in this logical form, the 20-line modem interface 40 must be translated into a form approved by the modem circuit 41. This is because a constant chirp signal is a low-frequency 90Vrms AC voltage and is normally received by the acoustic detection circuit DAA 20 (see Fig. 3). The 20 includes an optical coupler at its output end. This optical end is single τΐα — early data port g * early — ring signal. The signal is recognized (Figure 5 re-path 41. It refers to the computer to build the incompetent. The regulated one-bell DAA coupling 18 1244314 acts as a full-wave rectifier on the chirping voltage of the sinusoidal waveform. The ring-indicator signal in Figure 3 therefore includes a low-voltage, full-wave rectified sine in the frequency range of 15 to 6 8 Hz. Wave pulse. This signal is normally used for the input pin RINGIN of the controller 44 and then controls the 5 and 4 to measure the interval length of the pulse to determine whether the pulse is within a given frequency range of 15 to 68 Hz. As a background, the translation required on the ringtone simulator 62 includes, for example, a square wave oscillator operating in the range of 15 to 68 Hz, followed by a low-pass filter to round the square wave edge, and a full wave rectifier The 10 output thus becomes the desired ring indicator signal 6 1. As mentioned above, the signal in logic form is not recognized by the input pin RINGIN (or RINGD) of the commercial controller 44. In any case, return This full-wave rectified chirp signal, some controllers will generate a logic signal for input pin RINGD. This logic 15 series signal can appear on pin R1 or the controller's STSCHG for transmission to PC interface 45 and PC 13. In this example, it is possible to use this logical bell indication signal directly from the microprocessor 3 3 instead of the bell simulator circuit 62. The logic signal is therefore only applicable to the output signal at pin R1 or the controller 44 On STSCHG. 20 In order to respond to the incoming call, a hook switch control command is generated by the computer 1 3 and sent to the controller 44. Then it sequentially generates a hook switch control signal 5 4. The first step of this signal is to turn on the wireless modem. The power (ON or PHONE) of the transmitter 52 of the interface 40, and then establish a wireless connection 19 1244314 between the wireless modem card 12 and the near-end unit 1 1 and then send this hook switch control signal back to the near-end unit 1 1 (See Figure 2), which causes the telephone central office to transmit a dial tone, and return the wireless modem card 12 and PC 1 3 through the near-end unit 11. The hook switch control signal is generally used during the entire call. Keep 5 the same Voltage value. Wired option equipped with wireless modem 10 can also be configured with some circuits to operate as a wired modem. An example of a wireless modem 10 made with this circuit is shown in Figure 6. Figure 6 is incorporated The standard modem circuit includes a telephone line interface 20 and a composite circuit 55. The above two are similar to the corresponding circuits described above. The composite circuit 5 5 is resistant and consists of a balanced operational amplifier (terminals TXA 1 and TXA2 ), And a signal in the opposite direction is obtained by an unbalanced operational amplifier 15 (terminal RIN). These two operational amplifiers are standard functions of the modem circuit 41. Switches 5 6 and 5 7 select a wired or wireless operation mode from the two. These switches are implemented electronically (for example, using CMOS switches). When the telephone cord 18 is used for modem communication 20, they automatically operate. These switch control signals 28 are also called wired presentation instructions, which are generated by the wired presentation indicator circuit 27 of the telephone line interface 20. Circuit 27 shows an optical coupler connected to the input telephone line. Because there is always a dc voltage at the telephone central office that is always applied to the telephone line 18, the voltage 28 exhibits a voltage that is as long and constant as the telephone connection continues to exist. In particular, when the wired presentation indicator 2 7 detects the wired media, the switches 5 6 and 5 7 are triggered to operate the modem in the wired mode 5. When the wired presentation indicator 27 does not detect the wired media, these switches operate the modem in wireless mode. In addition, when operating through the telephone cord 18, the switching voltage 28 connected to the switch 5 8 is also used to close the wireless modem interface 40. The wireless modem 10 is not limited to use the hardware / 10 software configuration of Figs. 1 to 6; it can be any applicable computing or processing environment. The wireless modem 10 also does not restrict its transmission data in the radio frequency band as described above, or in the specific modulation technology described herein. Any technology and / or delivery method other than the foregoing may be used. The above-mentioned embodiments are merely examples for the convenience of description. The scope of rights claimed in the present invention should be based on the scope of the patent application, rather than being limited to the above-mentioned embodiments. _ [Schematic description] 20 Figure 1 is a block diagram of a wireless connection. FIG. 2 is a block diagram of a near-end unit used in a wireless modem. Figure 3 is a block diagram of a telephone line interface in a near-end unit. FIG. 4 is a block diagram of a wireless modem card used by a wireless modem. FIG. 5 is a block diagram of a modem circuit used by a wireless modem card. 21 1244314 Generation block diagram, including FIG. 6 is a wireless modem optional equipment for a “wired”. [Illustration of drawing number] 5 (10) Wireless modem (100) Data signal (101) Composite signal (1 1) Near-end unit (12) Wireless modem card 10 (13) Computer (14) Telephone line (15) Socket (16) RF link (1 8) Telephone cord 15 (19) Wireless modem card (20) Telephone line interface electrical maintenance circuit (22) Electronic noise detector (23) Overvoltage protection circuit (24) Bridge rectifier And loop straight g 20 (25) hook switch circuit (27) wired presentation indicator (28) switch control signal (29) transformer (30) composite circuit 22 1244314 (3 1) automatic gain control circuit (32) radio transmitter ( 33) Microprocessor (34) Radio receiver 5 (35) Duplexer (36) (37) Antenna (40) Wireless modem interface (41) Modem circuit (42) Encoder / decoder 10 (43) Digital Signal Processor (44) Controller (45) Computer Interface (46) A / D Converter (47) D / A Converter 15 (50) Duplexer (5 1) Radio Receiver (52) Radio Transmitter (53) Microprocessor (54) Hook off command 20 (61) Ring indicator (62) Snoring simulator

Claims (1)

1244314 92134434, revised September 1994 Scope of patent application: 1. A modem, which mainly includes: a near-end unit, which includes: a transmitter to send a data message # ϋ, and a circuit system that receives the original signal from a telephone line, and 5 from the original signal And the echo signal to generate a synthetic data signal, and maintain the peak voltage excursion of this beta to "^" within the linear amplification range of one of the transmitters; and-the communication card receives from the near-end unit wirelessly Data signal 'and perform echo cancellation on the data signal. 10 2. The modem described in item 1 of the scope of patent application, wherein 'the near-end unit communicates with the telephone line and receives the original signal from the telephone line' This near-end unit generates a radio frequency level based on the original signal. Multi-level Frequency Shift Keying (FSK) signal. 15 3. The modem according to item 2 of the scope of patent application, wherein the circuit system includes an automatic gain control circuit. 4. The modem as described in item 3 of the scope of patent application, wherein 'the automatic gain control circuit determines a gain of 20 by measuring the dial tone of the central office or the level of DC current from the central office of the telephone, and this The gain remains fixed throughout the communication process. 5. The modem as described in item 丨 of the scope of patent application, wherein the data signal is sent using Multi-level Frequency Shift Keying ° 24 I2®.P 6. The modem as described in item 1 of the scope of patent application, wherein the communication card communicates between the near-end unit and the PC, and the communication card receives an original signal from the near-end unit, and then based on this The original signal from the PC generates a radio frequency multi-level variable modulation 5 signal, and then sends this radio frequency multi-level variable modulation signal to the near-end unit. 7. The modem as described in item 6 of the scope of patent application, wherein the communication card includes a radio frequency transmitter and a radio frequency receiver, and the communication card establishes wireless communication with the near-end unit, as in 10-wireless telephone handset establishment It communicates with the near-end unit. This communication card communicates with the near-end unit wirelessly through its RF transmitter and receiver. This communication card communicates with the PC by wire, such as the same cable modem and a PC communication. 8. The modem as described in item 6 of the scope of patent application, in which the communication card includes a ringtone simulator and a ringtone detection circuit, and wherein a low-frequency signal generator is used to simulate, When a ringtone signal is detected in the near-end unit, it is sent to the ringtone detection circuit of the communication card in the air. This ringtone simulator simulates ringtone detection on a normal telephone interface and provides its signal to a Modem circuit to execute an incoming telephone call procedure 0 25 124431 ^ 9. The modem as described in item 6 of the patent application scope, wherein the communication card includes a switch to select a media form and send it on it And receive data signals. 10. A modem includes: 5 a near-end unit; a communication card to send data signals to the near-end unit, and the near-end unit to receive data signals. The communication card includes a switch to select a media form, and Send and receive data signals; and _ 10 a circuit system that should trigger the switch when the modem has a wired media interface, the circuit system includes a line presence indicator; where the line presence indicator detects a cable During media, the switch is triggered to operate the modem in wired mode, and when the wire presentation indicator does not detect wired media, the switch is triggered to operate the modem in wireless mode. 11. The modem as described in item 10 of the scope of patent application, wherein the media form includes a wired modem. · 1 2. The modem as described in item 10 of the scope of patent application, wherein the media form includes a wireless modem. 20 1 3. A modem includes: a near-end unit that is connected to a telephone line. The near-end unit includes a hook switch circuit that occupies the telephone line by drawing a DC current from the telephone central office battery. Provide an indication that a telephone line is ready to send data signals; and 26 如 as repair… .'- ”-'-π...-A communication card that sends data signals to the telephone line via the near-end unit. The telephone line receives data signals. The communication card contains switches to select the media form and exchange data with the near-end unit. 5 1 4. The modem as described in item 13 of the scope of patent application, wherein the media form includes a wireless mode. 27