TW382862B - Full duplex communication circuit with a transducer for simultaneously generating audio output and receiving audio input - Google Patents

Abstract

Full duplex circuits provied a bi-directional signal path at one port for transmit and receive signals and also provied separation between the transmit and receive signals at their respective ports. To accomplish this, the circuits employ amplifier configurations, including bilateral T hybrid and blanced impedance configurations. One application is in a transducer interface, where a single transducer is used as both a speaker/ear phone and a microphone. Another application is in a telephone line interconnect, where the telephone line interface simultaneously transmits and receives electrical signals representing audio data, e.g., voice data. The transducer interface drives a receive signal onto a transducer with virtually no loading to create audio output while simultaneously generating a transmit signal from audio input. The telephone line interconnect dives a transmit signal onto a transformer to transmit signal to a telephone line while simultaneously generating a receive signal from the telephone line. In both applications, the circuits provide a bi-directional signal path (simultaneous transmit and receive signals) at one port and achieve separation of the transmit and receive signals at respective transmit and receive ports. To eliminate feedback, the circuits simultaneously compress the unwanted signal and expand the other signal to produce an output signal that is 35-40 dB greater than the unwanted signal at the output.

Description

A7 ___ ^ _ B7 _ ^^ __ 5. Description of the invention (1) Inventive part The present invention relates to audio communication circuits, and more specifically, it relates to full 11 duplex communication; using converters as both microphones and A second examination of Yang's voice. BACKGROUND OF THE INVENTION In the documentation of a communication device, the term "full duplex" means that the device

·. ....... I '. I ............ Simultaneously send and receive signals. For the user, this means that he can speak and listen to the other party at the same time via the device. Conversely, "half duplex" in the file means that the device can only send or receive at one time, but not simultaneously. Full-duplex is obviously better than half-duplex communication because it enables both parties to communicate at a distance, just like face-to-face. However, full-duplex communication is more difficult to implement on a speakerphone because of issues with sound and electrical feedback. When the sound returns from the speaker to the microphone, acoustic feedback occurs. The same is true of electrical feedback, but it is an electrical signal representing audio input (signal sent to remote device) and audio output (signal received from remote source). When the transmitting and receiving circuits are not completely isolated from each other, electrical feedback occurs and a closed loop is formed with a loop gain greater than 1. To completely eliminate feedback, the entire loop gain, including sound and electrical effects, needs to be less than one. Most of the speakerphones printed by hands-free and group communication for employees' cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs have a half-duplex configuration...... To alternately: 1) broadcast the audio via a speaker: r. The audio output, and 2) listen to the audio input in another microphone. If you do n’t follow this exchange, because of the sound feedback path from the speaker to the microphone, the loudspeaker will growl. The switching circuit prevents the loudspeaker and the microphone from acting at the same time I. ..., and therefore, the output of the loudspeaker will not induce an electrical signal in the microphone -4- (Please read the precautions on the back before filling this page) The size of this paper is suitable. Use the Chinese National Standard (CNS) A4 specification (210X297 mm) A7 _ ^ _ B7___ 5. Description of the invention (2). Although the exchange function avoids howling: howling, it is troublesome because the user cannot speak and listen at the same time. The switching circuit compares the strength of the two-way broadcast signal and allows only the stronger of the two to be sent to the other party. Because full-duplex communication requires a completely closed loop to send and receive signals between the two positions of the talk at the same time, the overall path gain should be less than one. One way to ensure that the loop gain is less than 1 is to use digital signal processing to detect feedback and cancel it. A speakerphone using this method is sometimes called a digital full-duplex speakerphone. This device contains separate speakers and microphones, as well as analog-to-digital conversion circuits, which are transmitted and received by adaptive filters.... ,. Between the signal paths, the audio output of the received signal enters the loop through the microphone ........ The signal gain changes caused by the transmission part. Detecting this feedback in response, the device uses electronically controlled attenuators on each side of the loop to ensure that the loop gain is less than one. Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs To the extent that it is difficult for the user to hear. Often, the attenuator needs to reduce the gain of the received signal so that the user cannot hear the other party's voice. In addition to this disadvantage, the digital configuration is several times more expensive than the half-duplex speakerphone configuration. One way to solve the problem of sound feedback is shown in US Patent No. 4,002,860. This illustrates a communication device that uses a single converter as both a speaker and a microphone to eliminate sound feedback. The circuit design shown in this patent does not effectively eliminate electrical feedback. This circuit uses a so-called split transformer device to isolate the sending and receiving signals from each other. The telephone circuit used to provide isolation in this circuit can only provide about the paper size applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) -5-A7 B7 V. Description of the invention (3). 1 5 d B Isolation. The amount of isolation is highly dependent on how well the circuit can match the impedance of the converter and the telephone line. Because the circuit cannot isolate the sending and receiving signals, it is because of this that a large amount of feedback is generated. Another disadvantage of the circuit shown in the '860 patent is that the circuit applies a load to the converter & φ, the load on the converter will greatly damage the effectiveness of this circuit. Voice voice input is induced in the converter by 'transmitting letter f. In ordinary microphones, the signal induced by the user's voice is very small, about 10 m V. Any load on the converter draws the energy of the induced signal. To cope with this loss, the circuit used to process the transmission signal can amplify the small voice signal, but if any feedback is received to the amplifier in the transmission circuit, the feedback problem mentioned above is worsened. The invention is printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the notes on the back before filling this page). The invention provides a full-duplex audio communication circuit and related methods. Compared with the current full-duplex communication device, it has higher performance. The audio communication circuit uses a converter as a speaker to convert a signal received from an external source into an audio output; and a microphone to generate an electrical transmission signal. Used as a speaker and microphone, the output of this converter includes a combination of send and receive signals. In order to generate a transmission signal with minimal feedback, the communication circuit takes this combined signal and makes the received signal smaller than the transmitted signal. For example, one of the circuits is implemented to be able to generate a final transmission signal, wherein the transmission signal is 30 d B larger than the reception signal. -The communication circuit can use one or two types of circuits to simultaneously compress the received signal and expand the transmitted signal. This circuit is an expander-compressor. This pair of paper sizes applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -6-A7 B7 V. Description of the invention (4) Sending and receiving signals are simultaneously reduced Small receive signal and increase send signal. The expansion-compressor should preferably be implemented by a logarithmic amplifier, which expands the received signal and reduces the transmitted signal in a logarithmic manner. Another circuit also compresses the received signal and expands the transmitted signal at the same time. This uses a difference amplifier to eliminate the common-mode signal applied to its input. To be clear, the difference amplifier cancels the two in-phase received signals (audio input) from an external source, and generates an output signal having a transmitting signal portion and a substantially canceled receiving signal portion. One way to use a difference amplifier is to connect a matching converter with opposite polarity to each input of the difference amplifier. In this configuration, the received signal at the input of the difference amplifier is in phase, while the transmitted signal is out of phase. Because the difference amplifier subtracts the signal at its input, the output of the transmitted signal is approximately doubled, and the received signal is roughly canceled during the word. These two circuits can be used independently; or they can be combined into various configurations to reduce the received signal to the transmitted signal. Finally, the communication circuit can generate a final transmission signal, in which the transmitting part is greatly increased and the receiving part can be ignored. Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (read the notes on the back of the book before filling out this page) Take the combined sending-receiving signal and roughly cancel the ability to receive the signal, making the implementation of the communication circuit effectively reduce feedback . For example, in an implementation, the converter generates a transmission signal of about 3 mV, and simultaneously converts a received signal in the 300 m V range into an audio output. This implementation combines the compression-expander, and in a differential configuration, takes the combined transmission_reception signal and generates a transmission signal of about 30 OmV and at a level of 30 dB or lower than the transmission signal To receive signals. Another significant advantage of the communication circuit is that the circuit can be implemented without loading the converter or shunting it. In an embodiment, the paper size of the amplifier is connected to the Chinese National Standard (CNS) A4 specification (2 丨 0X297 mm) A7 B7 ___'_ 5. Description of the invention (5) to the converter to apply the remote source Receive the signal to the converter without adding load to it ~ The converter also avoids shunting of the received signal. Amplifiers come in a variety of other configurations. This avoids loading the converter. In one configuration, for example, the amplifier is implemented by an operational amplifier, and the received signal is applied to the non-inverting input, and the converter is connected to the inverting, input 鞴. Due to the characteristics of the operational amplifier in this configuration, the amplifier applies the energy of the received signal to the converter without adding load to the converter, or causes the received signal to be lost. The present invention provides a circuit that supports a bidirectional signal path for transmitting and receiving signals simultaneously on a single board, while maintaining separation between transmitting and receiving signals on individual ports. In telephone terminology, a port is equivalent to a pair of lines. Therefore, the present invention provides an interface between a 2-wire and a 4-wire configuration. This feature enables the circuit to support full-duplex communication while maintaining loop gain below 1 to cope with feedback issues. To achieve this, the circuit uses amplifiers arranged in a two-sided T-splice circuit or balanced impedance configuration. Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the notes on the back before filling out this page). Although applicable to a variety of applications, one of the inventions is mainly applied to telephone devices. In a telephone device, the present invention can be used as a converter interface and a telephone line interconnection circuit. In the converter interface, the present invention provides a two-way signal interface to a converter used as a speaker / headphone and a microphone. In a telephone line interconnection circuit, the present invention provides a two-way signal interface for transmitting signals at the same time. Telephone lines and receiving signals from telephone lines :. The converter interface circuit is driven to receive signals on the converter to generate audio output, and at the same time to generate a send signal from the audio input to the converter. The telephone line interconnection circuit drives a transmission signal on a transformer to send the transmission signal to the telephone line, while generating a reception signal from the ^ I ^ telephone line. In two applications, the circuit provides a two-way signal path. The paper is from the applicable Zhongguanjia standard ([called eight 4 wires (2 297 mm)) «« I Ι A7 B7_ V. Description of the invention (6) (Sending and (Received signal) on one port and achieve separation of the transmitted and received signals transmitted to each port. One aspect of the present invention is a bilateral τ-destructive circuit φ. The bilateral τ-combined circuit includes two operational amplifiers, which— The inverting terminal is connected to another non-inverting input. The node between s operational amplifiers provides a τ connector, which carries the combined outgoing and incoming signals. The configuration of the operational amplifier is received on its non-inverting input. A first input signal. Via the current mirror effect, this first input signal is also present on the inverting input and represents the outgoing signal portion at the τ connector. A second input signal in the circuit entering the τ connector represents The incoming signal. / Printed by the Central Consumers Bureau of the Ministry of Economic Affairs, Consumer Cooperatives (please read the precautions on the back, and then fill out this page). The bilateral t-splice circuit uses a difference amplifier to reduce the outgoing signal and increase the incoming signal. The first and second operational amplifiers each generate a common-mode signal portion, which is equivalent to the outgoing signal. Since this signal is presented in common mode, it can be cancelled by the difference amplifier. It is equivalent to a signal portion of the incoming signal presented to the amplifier as a common mode. On the output end, and this is not canceled by the difference amplifier. In fact, the incoming signal can be applied to the operational amplifier, and the part of the signal equivalent to the incoming signal differs by 180 degrees on the output end of the operational amplifier. .Because the difference amplifier adds 180 degrees of phase difference, the incoming signal is increased by the difference amplifier. In short, the bilateral T-splicing circuit supports two-way signal flow on the T connector, and provides an output signal, and Incoming signals are separated by equivalent signal portions. Another aspect of the invention is a balanced impedance configuration. In one implementation,-the operational amplifiers are connected together at their non-inverting inputs. The two operational amplifiers are arranged as a voltage feed. Input-current feedback configuration. It represents one of the incoming signals. The paper size applies the Chinese National Standard (CNS) Α4 specification (210X297 mm) -9- A7 ___ __B7___ 5. Description of the invention (7) The first input signal enters on the common mode of the two operational amplifiers connected to each other. This is presented on the output of the operational amplifier in the common mode, and as such, it can be cancelled by a difference amplifier. Feedback configuration, the incoming signal is transferred to a two-way device with little load, the device is connected to the feedback path of an operational amplifier (one or two operational amplifiers). The first two input signals enter the circuit of the two-way device, And the output end of the operational amplifier is not common mode. In this way, the output signal equivalent to the second input is not canceled in the difference amplifier. In a telephone line interconnection circuit, the bidirectional device can be a transformer, and this cross-linked circuit to the telephone In this application, the transformer transfers the incoming signal from the telephone line to the circuit, and the transmitting signal transferred from the circuit passes the transformer to the telephone line. In a converter interface, the bi-directional device may be a converter, such as a headphone or a speaker, which is used as both an audio output device and an input device. In this application, the converter sends the incoming signal from the audio input, and the circuit transfers the received signal to the converter, where it is converted to an audio output. Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economics Another aspect of the present invention is a telephone line interface in a telephone line interconnection circuit. The telephone line interface contains an analog inductor to regulate the current from the telephone line. The interface may also include an isolated circuit. When the current in the telephone line drops below a threshold or zero, this circuit opens the transmission signal path to the telephone line. In order to avoid feedback or roar in the telephone device, the loop gain of the feedback path for transmitting and receiving signals needs to be lower than one. Isolation circuits cope with this problem and ensure that when the phone's full switch is turned on, the send signal path is turned on. 1 The circuit described above has several points. When used in the converter interface, these support full-duplex communication via a signal converter. The circuit is valid as -10- (Please read the precautions on the back before filling this page) This paper size applies to Chinese National Standard (CNS) A4 specification (210X297 mm) A7 B7 ___ V. Description of the invention (8) Converter interface, Because it drives the converter to produce audio input Φ, it does not ......... .j. Load the converter. Basically, since the converter has no load, it can be used as a microphone to generate a transmission signal from an audio input. Moreover, this circuit deals with the feedback problem and roughly cancels the part of the received signal in the path of the transmitted signal. When used in a telephone line interconnection circuit, the circuit can be used as an interface because it provides% ......... a full-duplex signal interconnection circuit, which combines sending and receiving signals on the telephone line At the same time, the separation between sending and receiving signals is larger than that of ordinary telephone splicing circuit or resistance-capacitance cancellation circuit. Further advantages and features of the present invention will become apparent with reference to the following detailed description and accompanying drawings. Brief Description of the Drawings Figure 1 is a general block diagram showing the implementation of a full-duplex audio communication circuit. Figure 2 is a general block diagram showing another implementation of the audio communication circuit. Figure 3 is a general block diagram showing another implementation of the audio communication circuit.-Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page). Figure 4 is the essential diagram showing Detailed implementation of one of the full-duplex audio communication circuits. Figure 5 is a schematic diagram showing how more than one converter can be used on each side of a differential configuration similar to that shown in Figure 4 for higher power applications. Figure 6 is a schematic diagram showing another implementation of a full-duplex audio communication circuit

I 〇L— _._; _ ^ _ This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -11-A7 __; ______ B7 __'_ 5. Description of the invention (9) Shows how more than one converter can be used on each side of a differential configuration similar to that shown in Figure 6 for higher power applications. Fig. 8 is a schematic diagram showing another implementation of a full-duplex audio communication circuit. Fig. 9 is a schematic diagram showing a circuit using an additional microphone to increase a transmission signal in a full-duplex communication device. Figure 10 is a schematic diagram of a telephone interconnection circuit using one of the two-side τ splicing circuit configurations. · 'Figure 1 1 is a schematic diagram showing another telephone line interconnection circuit using a balanced impedance configuration. Figure 12 is a schematic diagram showing a converter interface using one of the two-sided τ splicing circuits. Figure 13 is a schematic diagram showing a converter interface using a balanced impedance configuration. Figure 14 is a schematic diagram showing the converter interface for a quartz converter using another balanced impedance configuration. Printed by the Employees' Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs (Please read the notes on the back before filling out this page)

Comparison table of main components 2 4 Compression-expansion circuit 4 8 Difference amplifier 1 2 4 Pass band equalizer 1 3 0 Operational amplifier 1 6 8 Automatic level control circuit This paper applies Chinese National Standard (CNS) A4 specification (210 X 297 mm) -12- Α7 Β7 V. Description of the invention (10) 222 and amplifier 2 7 2 linear amplifier 350 split transformer 5 0 〇 telephone interconnection circuit 5 2 〇 optocoupler · 522 isolation transformer 534 AC shunt capacitor 5 6 2 Detailed description of optoelectronic crystals The following details explain some implementations of full-duplex communication circuits. In telephony ... the words' these full-duplex circuits can provide bidirectional, '2-wire' signal paths for simultaneous TX and Rx signals, and provide two separate unidirectional signal paths for TX and ; RX signal (2 lines for TX signal, and 2 lines for Rx signal = 4 line). This type of circuit is sometimes called a 2 to 4 line circuit, or "split" circuit. In the case of ordinary telephone lines, The telephone line provides a two-way two-way signal path. '' The Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs printed the full-duplex circuit described below as a converter interface and a telephone line interface. As a converter interface, the circuit provides a two-way signal path It is located at the converter port and two separate unidirectional signal paths for the incoming and outgoing Rx and TX signals at the TX and RX ports respectively. As a telephone line interface, this circuit provides a two-way signal path at the telephone line And two separate one-way signal paths, which are used for RX signals from telephone lines and TX signals from telephone devices. -13- (Please read the precautions on the back before filling this page} This paper size applies to China Standard (CNS) Α4 Specification ( 210X297 mm) Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (11) It should be noted that this circuit can be used in a variety of communication applications. This circuit can be used in wireless telephone devices and special-purpose communication devices (such as .) In some applications, this circuit is used as a converter interface, but does not need to be a telephone line interface. In wireless communication devices, for example, Tx and RX signals are kept separate, and as such, there is no need for 4 to 2 wires Assemble and combine circuits to send and receive signals from communication devices. Converter interface Figure 1 is a general block diagram showing the implementation of a full-duplex audio communication circuit. The circuit includes a single converter 20 and an amplifier 22 connected To the converter, and a compression-expansion circuit 24 is connected to the output of the amplifier. The amplifier 22 receives the electrical input signal (received signal Rx) representing the audio input and transfers it to the converter 20, which then converts the received signal into audio Output. The converter 20 also changes the audio input, such as the user's voice is an electrical transmission signal (transmission signal Tx). Thus, the converter 20 functions For example, a microphone is used to convert the audio input into an electrical transmission signal, and a speaker is used to convert the electrical signal received from an external source into an audio output. Note that there is no sound feedback path because the speaker and the microphone are in the same position. It is implemented in a single converter. This eliminates the need to use an electronically controlled attenuator to reduce the effect of sound feedback. Since the converter receives the Rx signal and generates the Tx signal at the same time, there is a combination on the output of the converter 20 Send and receive signals (Tx + Rx). The amplifier 22 passes this combined signal to the compression-expansion circuit 24. The compression-expansion circuit 24 uses this combined signal and compresses it at the same time (I-—————— __I, -I__I II ding _ I _ ^ nn (Please read the notes on the back before filling out this page} This paper size is applicable to China National Standard (CNS) A4 (210X297 mm) -14-A7 B7 V. Description of the invention (12)

Rx signal and expanded (increased) Tx signal. The compression-expansion circuit 2 4 is preferably a logarithmic compressor-expander, which expands the T × signal and the compressed Rx signal logarithmically. The Tx signal induced in the converter 20 is usually much smaller than the Rx signal (approximately 30 OmV) applied to the converter, such as about 3 m V). The compression-expander design compresses signals in one voltage range and expands signals in another voltage range. The purpose here is to send the T X signal and substantially eliminate the R X signal to prevent feedback. To achieve this, the compressor-expander is designed to compress signals above a threshold voltage level and expand signals below a threshold voltage level. By compressing and expanding different parts of the signal at the same time, the compression-expansion circuit 24 can greatly increase the T X signal and greatly reduce the R X signal, and in this way, reduce the difference between the transmitted and received signals. The communication circuit shown here is "full duplex" because it sends and receives audio signals at the same time. When implemented in a telephone handset or walkie-talkie, for example, both ends of the line can simultaneously send and listen to each other's voice. Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page). One of the major advantages of this implementation is that the amplifier 2 2 avoids loading the converter 20. The amplifier 22 is designed to drive the converter 20 with minimal loss of received and transmitted signals. For best performance, receive signals should be applied to the converter with minimal load. Any load on the converter will cause part of the transmitted signal to be lost, which will seriously degrade performance, especially because the transmitted signal is usually much smaller than the received signal. Furthermore, the transmission signal should be generated without loss of the received signal in the converter. One way to avoid interference between the transmitted signal and the received signal is to place an impedance (shunt) between the converter and the source of the received signal. The shunting of the converter is not suitable, because this causes part of the received signal to be in accordance with the Chinese National Standard (CNS) A4 specification (210X297 mm) -15-A 7 ___B7 __ 5. Description of the invention (13) is lost . In this implementation, amplifier 22 is connected to converter 20 to avoid both converter load and shunt. Therefore, this amplifier can transfer TX signals with minimal loss, and can apply Rx signals to converter 20 with minimal losses. Figure 2 shows another implementation of the audio communication circuit, which is used when the signal level difference between Tx and Rx signals is small (that is, closer to the same level). This circuit includes two matched input stages, and each packet is converted one by one. Devices 40, 4 2 and an amplifier 44, 46. The input stages each act as described in Figure 1 above. However, note that the converters 40, 42 are connected with opposite polarities, so the transmitted signals in each input stage are approximately 180 degrees out of phase. The impedance of the input stage is balanced, so the received signals on each side are approximately equal in amplitude and phase, and the transmitted signals are approximately equal in amplitude, but the phases differ by 180 degrees. The circuit is printed by the Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs and contains a difference amplifier. The received and transmitted signals are used as inputs, and the transmitted signals are added together and the received signals are cancelled. Ideally, the output of the difference amplifier is proportional to the difference between the two input signals. Since the received signals are approximately in phase, they should be cancelled. The degree to which the received signals cancel each other out depends on the matching of the input stages. Ideally, the impedance of the input stage is matched; however, in practice, it is difficult to achieve a complete balance due to the differences in the devices. Therefore, if the input stages match, the received signal is roughly cancelled at the output of the difference amplifier 4 8, but not completely cancelled. It should be noted that the source of the received signal can and does fluctuate, and this will cause a phase difference in the impedance in each input stage. ^ It should be noted that there is no need to use a converter on each side, and a difference amplifier is used to eliminate the received signal. One of the converters can be equipped with a matching impedance device such as with -16-(Please read the precautions on the back before filling out this page) This paper size applies to China National Standard (CNS) A4 specifications (210X297 mm) A7 B7 V. Description of the invention (14) Replaced by inductor or RLC circuit with the same impedance characteristics as the converter. When a matched impedance device is used instead of a converter, the one without the converter obviously does not generate a transmit signal, but this is connected to the source of the receive signal and behaves similarly to the other with a poor configuration. The difference amplifier roughly cancels the received signal from each party and amplifies the transmitted signal from the party with the converter. -Although a converter is not required for each input stage of the differential configuration, using the same type of converter in each input stage has some advantages. One advantage is that the user can feel more real and present. For example, in the implementation where the matching converter is an earphone, the two earphones enable the user to hear the sound output in the two ears. If the converter is implemented as a speaker, such as a desk speakerphone, the speaker can be arranged to increase the sound output. The output signal of the circuit is relatively large, because the difference amplifier makes the signals of opposite polarity on each input terminal add up, which doubles the transmission signal. Moreover, using the same mode conversion device on each side, it is easy to achieve impedance and. Phase matching. Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page). In general, this circuit configuration has the same effect as the circuit in Figure 1, because it also increases the transmission signal and reduces receive signal. However, in the case where the separation between the .TX and RX signals is large, it is necessary to use both a compression-expander and a difference amplifier, so as to more effectively eliminate the RX signal in the combined Tx-Rx signal. The T X signal induced by the sound input in the converter is much smaller than the R X signal received from a standard telephone line. Compressor-expander Reduces the separation between the T X and R X signals. The differential amplifier more effectively cancels the common-mode R X signal as opposed to the T X signal. Fig. 3 is a block diagram showing another implementation of the audio communication circuit. This electricity ;: | The characteristics of the circuit shown in Figure 1 and Figure 2 of the road, because it uses a differential amplifier and the paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -17-Central Standard of the Ministry of Economic Affairs A7 ___B7__ printed by the Bureau ’s Consumer Cooperatives V. Description of the invention (15) Both the expander and expander to compress the received signal and increase the transmitted signal at the same time. The differential configuration in this circuit includes two input stages with matched impedance. The input stage of each party includes a converter (60, 62) and an amplifier (64, 66). The functions of these components are the same as those of the input stage shown in FIG. 2 and need not be described in detail here. Each of the difference configurations also includes a compression-expansion device (68, 70), which simultaneously compresses the received signal and expands the transmitted signal. The difference amplifier 7 2 receives the combined transmit and receive signals (TX + RX) from each party, cancels the received signals with each other again, and adds the transmitted signals m ° Figure 3 provides better performance than Figures 1 and 2, because the difference The configuration and compression-expander are combined to provide better cancellation of the received signal and amplification of the transmitted signal. As in the circuit of Figure 2, each party is suitable, but it is not necessary to have a converter. One side can be replaced by a matched impedance device. In this case, the party having the matched impedance device has a compressor instead of a compressor-expander because this party does not generate a transmission signal. 1 The circuits in Figures 1-3 each include an audio processing circuit connected to a conversion-'' device for receiving combined signals, including TX and RX signal parts, and used to expand the TX signal part and compress the RX signal part at the same time. Serving. The audio processing circuit can generate a T X signal larger than the R X signal, and the extent to which the R X signal is substantially eliminated depends on the relative levels of the T X and R X signals at the converter, and the specific configuration of the audio processing circuit. In FIG. 1, the audio processing circuit includes a compression-expansion circuit 24. This is particularly effective in reducing the difference between the T X and R X signals when the T X signal is much smaller than the R X signal. However, one compression and one expander is not enough to make the TX signal larger than the RX signal. This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -18-(Please read the precautions on the back before filling (This page),? Τ I ——_ Printed by the Central Standards Bureau of the Ministry of Economic Affairs and Consumer Cooperatives A7 B7 V. Description of the invention (16) and effective cancellation of the RX signal, because the TX signal generated in the converter is usually very small . In Figure 2, the audio processing circuit includes a difference amplifier 48. When the two input stages of the difference amplifier are well matched and the separation between the TX and RX signals is less significant, the phase with the TX signal is eliminated, and the X signal is particularly special. effective. However, 'unless the Tx and Rx signal bits are closer together, the difference amplifier alone is not particularly effective. Finally, in Figure 3, the audio processing circuit includes a joint compressor-expander 6 8, 7 0, and a difference amplifier 7 2. The audio processing circuit of Figure 3 more effectively eliminates the R X signal relative to the τ X signal. Because the compressor-expander first reduces the difference between the T X and R X signals, then the difference amplifier substantially eliminates the common-mode R X signal. The audio processing circuits of FIGS. 1-3 are described in more detail below. FIG. 4 shows a detailed implementation of a full-duplex audio communication circuit. Like the circuit P shown in Figure 3, this circuit uses both a differential configuration and a compressor-expander to simultaneously expand the transmitted signal from the converter and reduce the received signal from an external source. Each side of the differential configuration includes a converter 100, 102 ', an amplifier 1, 104, 106, and a compression-expander 108, 1 10. The compression-expander outputs 1 1 2, 1 1 4 on each side of the differential configuration are connected to a differential amplifier circuit 1 1 6. The output of the differential amplifier circuit 1 1 6 is connected to an output stage 1 1 8. This further expands the transmitted signal, compresses the received signal, and adjusts the output voltage level to a more uniform level. The output stage 1 18 generates a final transmitted signal 1 2 0 and a greatly weakened received signal, which is at least 30 d B below the transmitted signal. By compressing the received signal and expanding the transmitted signal at the same time, this circuit achieves Ί — ^.,:., TTο. (Please read the precautions on the back before filling this page) This paper is also applicable to China National Standard (CNS) A4 specifications ( 210X297 mm) -19- A7 B7 5. Invention Description (17) Full-duplex performance with minimal feedback. The input received signal 1 2 2 enters a passband in the circuit. Equalizer 1 2 4 places. In this particular configuration, the passband equalizer is implemented using a normal bipolar passband equalizer circuit. The passband is equalized. The converter 1 2 4 equalizes the audio output at converters 100, 1, 02. Specifically, the frequency response of the received signal tends to decrease at higher frequencies. In order to equalize the frequency of the received signal ...... ........, The passband equalizer has a reactance circuit that offsets and balances the frequency response of the received signal. Printed by the Consumers' Cooperative of the Central Bureau of Standards, Ministry of Economic Affairs (please read the notes on the back before filling this page) -0. The passband equalizer 1 2 4 output 1 2 6 is applied to each side of the poor configuration Amplifiers 1 0 4 and 10 6. Figure 4 shows one method of applying the received signal to the converter, using an amplifier, without adding load or shunting the converter. In this implementation, the amplifier 104 includes an operational amplifier 1 2 8 and has a resistor R 1 1 3 0 connected across the inverse of the operational amplifier 1 3 4. The phase input terminal 1 2 and the output terminal. Any type of common operational amplifier circuit can be used to implement the circuit, including but not limited to LM3 2 4 or TL operational amplifier. This also applies to the operational amplifier used in other embodiments. After passing through the passband equalizer, the received signal enters the non-inverting input terminal 1 3 6 of the operational amplifier. The inverting input 1 2 of the amplifier is connected to the converter 100 and the other end of the converter is grounded. Because the current mirror bias of the operational amplifier 1 2 8 acts as a current source, the operational amplifier 1 2 8 receives the Rx signal at its non-inverting input terminal and drives the Rx signal into the converter through its inverting input terminal 1 2 2 1 0 0 in. The inverting input 1 2 is on virtual ground, which means that its voltage to ground is close to zero. Because the virtual ground cannot absorb the current, the paper size of the RX signal is in accordance with the Chinese National Standard (CNS) A4 specification (210X297 mm) -20 · A7 B7 V. Description of the invention (彳 8) An input current is forced to pass R 1 1 3 0. Therefore, the voltage gain of the 'amplifier 104 is equal to-R 1 / Z 1. A negative sign indicates a phase shift between the input and output of the op amp. Moreover, since the inverting input terminal is on the virtual ground, the input impedance of the amplifier is equal to z 1, that is, the impedance of the converter 100. This unique method of loading and shunting the converter due to the drive of the converter 100 allows the amplifier to transfer small electrical signals (about 300 microvolts) converted by the converter's audio input to the operational amplifier. The output is negligible. The amplifier 106 on the other side of the difference configuration has the same design as the amplifier 104 on the other side. However, the converter 102 is connected to the amplifier 106 and has a polarity opposite to that of the converter 100 on the one side of the differential configuration. This enables the differential amplifier circuit 1 16 to approximately double the transmission signal received by each side of the differential configuration. It should be noted that, as mentioned above, the converter 102 can be replaced by a device such as an inductor, and the rotation on that side of the matching differential configuration (the impedance of the converter 100). When a matching impedance replaces the converter 102 This side of the circuit only contains the received signal, and therefore there is no need to compress the expansion part of an expander 110. 'Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling this page -The converters 100, 102 are shown as earphones in Figure 4, because this circuit is particularly suitable for portable communication devices that use earphones. The audio communication circuit shown here also uses speakers instead of earphones, such as desktop speakers On the phone. Regardless of whether the circuit is used in a portable device using a headset or a desktop speakerphone, the converter should have a relatively high impedance, which can respond to voice input and generate a larger Tx signal. It has 100 Ω and 6 〇0Ω speakers i and other high-impedance converters can be obtained from Kobitone Audio Co., Ltd. and this paper size can apply Chinese National Standard (CNS) A4 specifications (210X297 mm) _ 21 · A7 _________B7__ 5. Note (19) can be obtained by other manufacturers. Kobitone Audio also manufactures high-impedance headphones. Although I mentioned a specific type of converter, it should be emphasized that a number of other converters, including headphones and speakers, can also be used to implement the invention. This also Applicable to the implementation of Figure 4 and other implementations described and shown in this document. · Before the application of the speakerphone, the design consideration is the geometric orientation and polarity of the speaker. Consider the circuit of Figure 4 Based on one of the speakerphone applications. Because the speakers have opposite polarities, the sound output of each speaker tends to cancel each other out. One way to avoid this cancellation is to set the speakers back to back (pointing in opposite directions / phase separation 180 degrees) ). In the case where the speaker is often faced by a speakerphone, this is one of the sufficient solutions to solve the problem, but it will generate a one along a direction perpendicular to the two speakers and passing through a plane between the speakers. "Zero" or dead zone. Another solution is to connect the second speaker (1 0 2) in Figure 4 between point A and ground, with the same polarity as the first speaker (100). Because the two speakers have the same polarity, this additional design avoids the problem of the output of one speaker eliminating the output of the other speaker. However, when the connection is amplified, it is printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the note on the back first Please fill in this page again when the operational amplifier in device 1 0 6 is placed at A on the output of the amplifier. The converter sees the load of the output impedance of the operational amplifier. This load basically prevents the converter from generating a Tx signal at This side of the difference amplifier (point A). However, this configuration does have the advantage of increasing the sound output, because the two converters still convert the received signal into an audio output signal. This question about the position and polarity of the speakers also applies to the following Other implementations described. However, this question is not particularly relevant to the use of headphones, as the audio output of each headphones is isolated from each other in sound. '' This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -22-A7 B7 V. Description of the invention (20) The output signals of the amplifiers 104, 106 are fed to each of the differential configurations. The same compression at one side-the dilator 1 0 8, 1 1 0. In the implementation shown here, the compression-expander is implemented using a common tensioner IC. Tensioning circuits are available from several manufacturers, including Toko Semiconductor (tensioner I c 1: K 1 065 5 Μ), San.yo Electronics (!; LA 8 6 3 2 Μ), and Motorola Corporation ( MC33110) 1 _. Compression-expanders are mostly constructed to compress larger receive price numbers and expand smaller transmit signals. After being amplified in the amplifiers 104, 106, the received signal is 15 to 30 times larger than the transmitted signal generated by the audio input of the converter. Thus, the received and transmitted signals at the inputs of the compressor-expander 108, 110 are approximately 20: 1 ratio. In this implementation, the tensioner log-compresses the received signal and expands the transmitted signal. The ratio of the received signal to the transmitted signal at its output is reduced to about 6: 1. Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page) The difference amplifier circuit 1 1 6 receives the output of the compressor-expander (at nodes 11 2 and 11 4) and generates An output signal, where the transmitted signal is greater than the received signal. The difference amplifier circuit 1 16 in this implementation includes a difference amplifier 150 and resistors R3, R4, R5, and R6 (152-158). The resistors R3 and R5 are connected between the respective output terminals of the compression-expander and the two-input terminals of the difference amplifier 150. The resistor R 4 is connected between one of the input terminals and the output terminal of the difference amplifier, and the resistor R 6 is connected between the other input terminal and the ground. The larger received signal becomes common-mode feed to the difference amplifier circuit.

The net elimination on the output side is approximately 3 0 — 4 0 d B * ί below the original level on the input side. Compressor-expander is almost doubled, the smaller transmission signal is in accordance with the Chinese national standard (CNS) A4 specification (210 × 297 mm) -23- A7 B7 in the paper size of the difference amplifier. These signals are of opposite polarity. The output of the difference amplifier produces a combined transmission and reception signal, in which the transmission part of the signal is 20-30 dB larger than the unwanted reception part of the signal. The output signal of the difference amplifier circuit 116 is fed to a level transfer circuit in the output stage 118. Contains resistors .R7 and R8 1 6 0, .1 6 2. The level transfer circuit is used in this implementation to adjust the level of the signal at the input of another compressor-expander 1 6 4. This special compressor-expander 1 64 further expands the transmitted signal and compresses the received signal. Since the level of the transmitted signal is greater than the received signal at this point, the compressor-expander 1 6 4 in the output stage is set to generate a larger signal above a certain threshold voltage level and generate a certain threshold Smaller signal below level. The level shift circuit ensures that the input of the compressor-expander is at an appropriate level, and that the compressor-expander functions properly. Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back of the H before filling out this page) In this specific implementation, the compression-expander 1 6 4 is also implemented using a common tensioner IC. This tensioner produces a greater separation between the TX and RX signals. In this circuit part, the tensioner increases the difference between the T X and R X signals, and at the input stage, the tensioner reduces the difference between the T X and R X signals. Due to this simultaneous compression and expansion, the resulting output signal contains only negligible received signals, that is, the transmitted signal portion is approximately 35-40dB larger than the received signal portion. Therefore, any feedback of the received signal to the output of the transmitting channel is almost completely eliminated. The output stage 1 18 also includes an automatic level control circuit 16 8 which receives the output of the compressor-expander 16 4 and adjusts the output to a more uniform output level. This automatic level control is particularly applicable to telephone communication. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) -24- A7 B7___ V. Description of the invention (22) Useful, among which, the sending signal should be fairly even About a 5 d B m. The full-duplex communication circuit shown in Figure 4 has several advantages. The unique configuration of the op amp as opposed to the converter prevents any loading or shunting of the converter. As a result, the small electrical signal transferred by the amplifier is transferred from the audio input to its output with negligible losses. Moreover, the received signal is prevented from interfering with the transmitted signal without shunting the received signal. Shunting will reduce the power of the received signal and make it difficult for the user to hear. Another advantage of this circuit is the combined use of a compressor-expander and a differential configuration to substantially eliminate the need to receive signals from the output of the communication circuit. The tensioner and the difference amplifier increase the transmission signal and compress the reception signal at the same time, and almost eliminate the feedback. The full-duplex communication circuit shown in Figure 4 is especially suitable for headsets. Among them,... '.. · Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling out this Page) The converter is used as both a headphone and a microphone. When the converter is implemented in a headset, the circuit requires less power to generate an audible signal because the headset is placed close to the user's ear. This circuit can also be implemented in a speakerphone, where the converter is implemented in the speaker, which serves a dual function, which is to convert the received signal into an audio output and the audio input into a transmitted signal. However, when the circuit is implemented in a speakerphone, more power is required to produce a sufficient level of audio output for the user to listen to while standing away from the speaker. In addition, the converter needs to be able to generate sufficient transmission signals, even when the audio input is from a source several feet away. One way to make the communication circuit shown in Figure 4 more effective for higher power applications is to use an additional converter. The combined audio output of these converters is easier to hear, and the transmission signals generated by these converters can be combined to produce a larger transmission signal, using a larger sound energy area, and maintaining this paper scale is applicable to China Standard (CNS) A4 specification (210X297 mm) -25- ~ 'A7 B7 V. Description of the invention (23) It is composed of multiple converters on the same electrical gain. Note that using multiple converters in this way increases the T X signal without increasing the loop gain. Figure 5 is a schematic diagram showing how multiple dual-purpose converters can be combined for higher power. In this circuit, the input stage is the same as the input stage shown in Figure 4, except that τ additional converters are connected to each side of the hearing configuration. The received signal from an external source enters the passband equalizer 200 of the circuit, and the frequency response of the equalized signal. The received signal is then fed to amplifiers 210, 212, 214, 216, which have a configuration which is similar to that of the amplifier shown in FIG. / The converters 202, 204, 206, and 208 are each connected to a corresponding amplifier 210, 212, 214, 21 6 in such a manner that each converter is connected to the amplifier in the input stage shown in FIG. On each side of the differential configuration, the output of the amplifier (such as 2 10, 2 1 2 is passed through the resistor on the output of the amplifier (such as R 9 and R 12; (Read the precautions on the back of the first cabinet, and then fill out this page) 2 18 and 220) Connected together. The combined output of the amplifier is fed to the inverting input of a sum amplifier 2 2 2. The sum amplifier consists of an operational amplifier and A first resistor R 1 1 is connected across its inverting input terminal and output terminal, and another resistor R 1 2 is connected between its non-inverting input terminal and ground. It can combine multiple inputs with the amplifier at the same time. Because the virtual ground is on the inverting input of the operational amplifier. In this configuration, the sum amplifier produces an output equal to the sum of these multiple inputs, which is amplified to equal the gain of the sum amplifier. 'Difference configuration The other side is implemented in the same way. The output of the amplifier 2 1 4 and 2 1 6 on the other side of the differential configuration is via resistors R1 3 and

I This paper size applies Chinese National Standard (CNS) A4 specification (210X297 mm) -26- Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs A7 ____ B7_ V. Description of the invention (24) R 1 4 Connect to and amplifier 2 2 The inverting input of one of the eight operational amplifiers. The resistors R 1 5 and R 1 6 are connected to the other side of the difference amplifier in the same manner as the resistors R 1 1 and R 1 2. The front-end stage design is connected to a difference amplifier. The rest of the circuit and its function should be implemented as shown in Figure 4. For the sake of drawing, simple, the output terminals of the amplifiers 2 2 2 and 2 2 8 are marked with the letters A and B, and 俾 corresponds to nodes A and B in FIG. 4. The front end stage shown in Figure 5 can replace the left front end stage of the nodes marked A and B shown in Figure 4. '' The use of multiple converters as shown in Figure 5 is advantageous for speakerphone applications because the output of each converter is combined to produce a complex ^-audio output that is easy to hear. Moreover, the electrical signals converted by the audio input of each speaker can be combined to produce a larger transmitted signal. To add even more converters, more pairs of amplifiers and converters can be combined as shown in Figure 5. By using multiple converters, the circuit can generate greater sound power and achieve greater sound geometric sensitivity. Moreover, low-power operational amplifiers (microwatts) can effectively process the received and transmitted signals generated in the converter. Figure 6 is a schematic diagram, 'shows another implementation of a full-duplex audio communication circuit. This circuit has a front end that uses a transistor to support two functions: 1) This drives a converter from a received signal from a distant source; and 2) This amplifies the transmission signal generated by the converter from the input. The received signal enters the passband equalizer of the circuit at 250, and the frequency response of the balanced signal is. The output of the passband equalizer passes a capacitor C 1 2 5 2. Resistors R1 (258) and R2 (254) form a voltage divider, which provides the required bias voltage to the transistor 2 56. Capacitor connection pass band equalizer (read the notes on the back of the reader first and then fill out this page) Order-This paper size applies the Chinese National Standard (CNS) Α4 specification (2! 〇 × 297 mm) -27- ___B7_ V. Invention Explanation (25) The input mode of the output of 2 5 0 to the common emitter configuration of a bipolar junction transistor 2 5 6. In this implementation, the transistor amplifier includes an NPN transistor 2 5 6 and four resistors 111, 112, 113, and 114 (2 58, 254'2 6, 0,262). The crystal amplifier is connected between the supply voltage Vcc and ground. The resistor R1 is connected between the supply voltage and the base of the transistor, and the resistor R2 is connected between the base of the transistor and the ground. The emitter is connected to the output of the converter 2 6 4 via a resistor R 4. On the collector side, the collector is connected to a matched impedance or converter 2 6 6 via a resistor R 3. A converter or matching impedance device 2 6 6 on the collector is connected between the supply voltage and the resistor R 3 2 6 0. Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling this page). The impedance balance at the collector and emitter of the transistor, so the transistor can generate Equivalent outputs, in which each output generates a received signal ;: the two are out of phase with each other. Because the transistor acts like an inverter on the signal applied to the input of the common emitter configuration, the received signal at each output is out of phase. One of the outputs is inverted, so the resulting signals each include an in-phase received signal. The second signal is then 'supplied' to the difference amplifier to eliminate the received signal. The impedance matching on the collector can be implemented using a converter that is the same as the converter 2 6 4 on the emitter, or using a device with matching impedance on the converter Z 6 4. The communication circuit shown in Figure 6 uses a transistor as an amplifier to form a common emitter and common base configuration. The current gain of the two common emitter and common collector configurations is equal to the beta of the transistor. Similarly, the voltage gain of the common emitter and common base configurations is equal to the collector impedance divided by the emitter impedance (Rc / R ~ e). This paper size is applicable to the Chinese National Standard (CNS) M specification (210 X 297 mm). ) -28-Printed by the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs A7 B7 V. Invention Description (26). In the case of a bipolar transistor, "" common "~ means the common terminal of the transistor as both input and output. Therefore, in the common emitter configuration, the emitter terminal is shared by both the input and output. Similarly, in the common base configuration, the base terminal is shared by the input and output. In the common emitter configuration, the input node is the cathode of the transistor and the output node is the collector. In the common base configuration, the input node is the emitter of the transistor, and the output node is the collector. The transistor amplifier shown in Figure 6 amplifies the received signal and uses a common base configuration. The transistor 2 5 6 amplifies the current of the received signal applied to the base electrode by an amount equal to the current gain of the transistor. The voltage across converter 2 6 4 is approximately equal to the received signal voltage minus the voltage drop from the base to the emitter (approximately .7 volts) and the voltage drop across resistor R4. The converter 2 6 4 converts the audio input into a transmission signal at the output of the converter. This transmit signal is applied to the input terminal of the transistor 2 5 6 in the common base configuration. Thus, the transmit signal_ accepts a voltage gain, which is equal to the voltage gain of the common emitter configuration. The amplifier configuration shown in Figure 6 provides an effective way to drive the converter with very little load. Any load applied to the converter will greatly reduce the drawing signal, because the converter generates a very small electrical signal from the audio input. Therefore, a major advantage of this configuration is that it drives the converter without a small load. Another advantage of this configuration is that due to the amplifier's voltage gain ', the transmitted signal receives a large amount of amplification. The two outputs of the transistor amplifier in Figure 6 are fed to the opposite side of the differential configuration. The output of one of the differences is taken from the collector of transistor 2 and supplied to inverter 270. The inverter inverts the part of the sending and receiving signals. The paper size applies the Chinese National Standard (CNS) Α4 specification (210 × 297 mm). -29-(I read the precautions on the back of the book before filling in this page), -β ί r

Printed by the Consumer Cooperatives of the Central Sample Bureau of the Ministry of Economic Affairs A7 _B7 __ V. Description of the Invention (27), 俾: 1) The transmitted signals on the two sides of the difference amplifier are out of phase, and 2) The received signals on the two sides are in phase. The received signal at the collector of transistor 2 56 is out of phase with the received signal at the base of transistor 2 56 because, as mentioned above, the transistor functions as an inverter. Therefore, in order to make the incoming signals on the two sides of the difference configuration equal and in phase, the received signals output on the collector must be inverted. The output of the other side of the difference configuration is taken at the output of the converter 264. At this output node, the received signal is in phase with the received signal applied to the input of the transistor, but out of phase with the output of the collector of the transistor. The transmission signal generated by the converter 264 is in phase with the transmission signal at the output of the transistor. The combined transmit and receive signals at the output of the converter are applied to a linear amplifier 2 72, which has a gain equal to the gain of the inverter 27 0. This linear amplifier 2 7 2 amplifies the combined transmission and reception signals and provides them to the other side of the difference configuration at its output. In this implementation, the inverter 270 is implemented using an operational amplifier and resistors R4, R5, and R6 (270, 278, and 280). The gain of the inverter is equal to R5 / R 4. The linear amplifier 272 is implemented in the same way, except that the input is applied to the non-inverting input of the operational amplifier 290. The linear amplifier 2 7 2 includes an operational amplifier 2 9 0 and resistors R7, R8, and R9 (2 92, 2 94, and 296), and has a gain equal to R8 / R7. The output of the inverter 2 70 and the linear amplifier 2 7 2 is applied to a differential i amplifier, which adds the transmitted signals from both parties together and makes the received letter (please read the precautions on the back before filling this page)

This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -30-A7 _B7_ V. The description of the invention (28) is roughly cancelled. To achieve better performance, the output of the inverter and linear amplifier is applied to the same compression-expansion circuit, which simultaneously compresses the received signal and expands the transmitted signal. One implementation method is to apply the output of the inverter and linear amplifier to the nodes of A and B of the compression-expander 1 08, 1 1,0 shown in FIG. 4. The rest of the communication circuit can be implemented in the same way as the circuit shown in FIG. Figure 7 is a schematic diagram showing how more than one converter can be combined for high-power applications. In this circuit, the converters are each paired with an electric crystal amplifier, using a configuration similar to that shown in FIG. Instead of a single transistor with matching impedance at the collector and emitter, this circuit uses paired complementary input stages on each side of the differential configuration (for example, 3 2 2 and 3 0 6 are complementary, and 3 0 4 and 3 0 8 complementary). Each input stage includes a transistor amplifier and a converter, the latter being connected to the emitter of the transistor of the amplifier. The input stages on the factory side of the configuration each include a complementary input stage on the other side of the configuration. An additional input stage can be added to each side of the difference configuration, and the output of each input stage can be added using the amplifiers 3 14, 3 1 6. : Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page). In this implementation, an input stage (such as 3 0 2) is connected to a common emitter configuration on the received signal. And connected to a common base configuration on the transmission signal induced in the converter. The configuration and function of the input stage are similar to the transistor amplifier of the input stage shown in FIG. However, since there is a complementary front-end stage on the other side of the differential configuration, a matching impedance device is not required in the collector to balance the impedance of the converter at the emitter. The received signal enters the input stage via the capacitor C 1 3 2 0 and passes through to the input node of the base of the transistor. A first resistor R 1 is connected to this paper. It is applicable to Chinese National Standard (CNS) A4 specification (210 X 297 mm) -31- Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (29) Between VCC and the base, and a second resistor R 2 is connected between the base and the ground. A third resistor is connected between Vcc and the collector. The output of the anode is provided on the collector. This connection is connected to the Yihe amplifier via capacitor C 2 and resistor R 4. The design of the other input stages is the same. The input stages 3 06 and 3 0 8 on the other side of the difference configuration each have a converter connected with opposite polarity. This full-duplex circuit has the same advantages as the circuit shown in Figure 5, because it can achieve greater sound geometric sensitivity and produce higher power output. Moreover, the use of multiple converters also allows the circuit to generate much larger transmission signals. The combination of converters in multiple input stages also allows lower power electronics to be used as amplifiers. Fig. 8 is a schematic diagram showing another implementation of a full-duplex audio communication circuit. This circuit uses a pair of ordinary split transformers 350 and 35 2 to connect the receiver of the communication circuit to a receiving line 3 4 0. The receiving line carries the incoming signal from a remote source and connects the sending of the circuit to the sending line 3 4 2. The signal carried by the transmission line. The transmit and receive lines carry both transmit and receive signals. The pair of split transformers 3 50 and 3 5 2 are connected together and connected to a balanced impedance 3 5 4. The transmitting and receiving parts of the communication circuit (respectively 3 4 4 and 3 4 6) are substantially isolated from each other. When a transmission signal is applied to the pair of split transformers, an equal, but opposite signal is induced in each split transformer. As a result, the transmission signal is transferred to the transmission line 342, but is substantially isolated from the receiver. Similarly, the received signal entering through the receiving line 3 40 is transferred to the receiving side 3 4 4 of the circuit, but is substantially isolated from the sending side. j The receiving part of this circuit amplifies the received signal and feeds it to the connection cost. The paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -32-(Notes on the back of Shi Xianmin, please fill out this page)

Α7 Β7 V. Description of the Invention (30) One of the differential configurations is an input stage. The receiving part of the circuit includes an amplifier 3 5 6 which amplifies the received signal from the pair of split transformers and applies the signal to each input stage. In this particular implementation, the 'amplifier 3 5 6 is a common operational amplifier, shaped like a linear amplifier. However, a variety of ordinary amplifier circuits can also be used. … .. Printed by the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page). Although it is not specifically shown in Figure 8, one of the same expansion circuits as above can be added to the assembly. Transformers and amplifiers between 3 5.6. This expander can be used to increase the separation between the R X signal and the T X signal (leakage from the T X side through the split transformer). In some applications, the incoming R X signal can be dropped quite low due to the attenuation effect on the communication line. At the same time, because the split transformer does not provide sufficient isolation, the T X signal leaking to the R X side may be higher. Due to these problems, an expander (e.g., 'from the tensioner 1c') can be used to expand the Rx signal to increase the separation between Rx and Tx. ~ Each input stage includes a converter connected to the amplifier, which transfers the received signal to the converter without loading it. The configuration of the input state shown in Figure 8 shows another way to drive the converter with the received signal, while reducing the load to a minimum. It should be noted that this particular circuit used to drive the converter can also be used to replace designs such as shown in the input stages of Figures 4 and 5. In the input stage shown in Fig. 8, each of the amplifiers is implemented by an operational amplifier 3 6 6 _ 3 6 2 with a resistor connected between the ground and the inverting input terminal of the operational amplifier. The received signal is fed to the non-inverting input of an operational amplifier, which is shaped like a voltage-to-current converter. The converter is connected between the output of the converter and the inverting input of the operational amplifier. The converters are connected with opposite polarities! 'On each side of the differential configuration. The paper size produced on the output end of the input stage applies the Chinese National Standard (CNS) Α4 specification (210X297 mm) -33- A7 B7 V. Description of the invention (31) The signals sent are equal, but the polarities are opposite. Conversely, the received signals generated at the output of the input stage are about the same, assuming that both sides of the difference configuration are balanced. The input stages each generate a combined signal, including the send and receive signals. Only the transmitted signals are out of phase. The combined signal from each input stage is fed to a difference amplifier 3 7 0. This roughly cancels the received signal and doubles the transmission. signal. The difference amplifier passes its output signal to an amplifier 3 72, which further amplifies the signal. The amplifier 3 7 2 is implemented using a common operational amplifier and is shaped like a linear voltage amplifier. Since a 6 0 0 Ω converter is used in this implementation, the amplifier 3 72 needs to be able to drive a 6 0 0 Ω load. The signal at the output of the amplifier 3 72 mainly includes an amplified transmission signal and a small portion of the reception signal. The degree to which this circuit eliminates feedback depends on the use of a split transformer to make the transmission ... ...... ..... ...... (Please note this page before filling out this page) and isolation between the receiver and the use of a difference amplifier to achieve the amount of cancellation of the received signal. Consider an example, where the incoming signal on the receiving line is approximately 3 OmV and the outgoing signal on the transmitting line is approximately 300 m V due to the attenuation effect on the incoming line. The following table shows the signal levels at various points of the circuit in the first case, where the receiver amplifier has a gain of 100, and in the second case, the receiver amplifier has a gain of 50. This paper size applies to China National Standard (CNS) A4 (210X297 mm) -34-

7 B V. Description of the invention (32)

Position gain in circuit 100 Gain 50 Output of receiver amplifier 356 Rx = 3V Rx = 1.5V Output of each output stage accounts for --- m Rx = 3V; Tx = 15Mv. Rx = 1.5V; Tx = 15mV Output of the difference amplifier 370 (assuming that the received signal is reduced by 30dB) Rx = 100mV; Tx = 30mV Rx = 50mV; Tx = 30mV Output of the sender amplifier 372 Rx = lV; Tx = 300mV Rx = 0.5V; Tx = 300mV Send line Rx = lV; Tx = 300mV Rx = 0.5V; Tx = 300mV Receive signal feedback to the sender (assuming about 30dB isolation) Rx = 33mV Rx = 1 6.6mV (Please read the precautions on the back before filling this page ) Order printed by the Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs. Note that there is some feedback in this circuit, and the feedback increases with the gain of the receiver amplifier. Moreover, the degree of feedback depends in part on the isolation effect achieved by using the pair of split transformers with balanced impedance. Therefore, the performance will vary depending on the degree of balanced impedance matching the characteristic impedance of the communication line. In some speakerphone applications, the communication circuit may need to produce a larger audio output. For example, if implemented on a speakerphone designed for use in a larger room, the user may want the speakerphone to produce an R X signal with a larger audio output. This will cause problems in dual-use applications, because the paper size of the RX signal is increased by the Chinese National Standard (CNS) A4 specification (210X297 mm) -35- Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7____ 5. (33) The gain makes it difficult to effectively reduce the RX portion of the TX signal. One way to solve this problem is to install additional converters such as microphones to add additional T X signal sources. These new T X signal sources can be added together 'to effectively expand the final T X signal output of the circuit. One problem that comes with this method is that the microphone receives both the voice signal and part of the audio output from the device's dual-purpose speaker / microphone as inputs. As such, the signals generated by the additional microphone include: 1) the voice input signal, and 2) the signals provided by the dual speaker / microphone output. In order to effectively expand the T X signal as opposed to the R X signal, the circuit should try to remove the signal of formula 2. FIG. 9 is a schematic diagram showing a method for increasing a TX signal while removing a signal related to a speaker / microphone output. In this circuit, two additional microphones 400, 402 are connected to the respective input stages of the differential configuration. The input stages each include a linear amplifier 404, 406, which receives the signal generated by the microphone and transfers it to one of the input terminals of the difference amplifier 408. The linear amplifiers each include a common operational amplifier 4 1 0, 4 1 2. The resistor R Γ is connected between the output terminal of the operational amplifier and its inverting input terminal, and the resistor R 2 is connected between the inverting input terminal and the ground. between. The gain of the amplifier is R1 / R2, and therefore it can be used as a multiplier or divider, depending on the resistances 値 R 1 and R 2. Note that the microphones 4 0 and 4 2 are connected to their respective linear amplifiers with opposite polarities. The voice input enters the microphone in the same phase, but it is transformed into a voice signal with a phase difference of about 180 degrees at the output terminals of each speaker 4 0, 2 0 2. Used as a subtractor, the difference amplifier 4 0 8 is almost doubled. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) -36- (Please read the precautions on the back before filling this page) Ministry of Economy Printed by the Consumer Standards of the Central Bureau of Standards A7 B7 V. Description of Invention (34) Input signal part provided by audio input. The microphones are each paired with speakers / microphones 420, 422 from another part of the circuit and have opposite polarities. Because the speakers / microphones have opposite polarities, the audio outputs of the speakers / microphones are each 180 degrees out of phase with each other. One of the arrangements of this circuit is to remove the signal generated in the microphone due to the audio output of the associated speaker / microphone. As a result, the speakers / microphones 420, 422 should each be paired with a microphone 400, 402, and each microphone accepts to enter it with a phase difference of 180 degrees from the input to the other microphone. Audio input, and transform this input into an in-phase electrical signal. This enables the difference amplifier to be subtracted from the input provided by the associated speakers / microphones 4 2 0, 4 2 2 to the microphones 400, 402. For example, if such a circuit is used in the circuit of FIG. 8, the microphone 4 0 0 can be paired with the speaker / microphone 3 5 8 (_4 2 0 in this figure), and the microphone 4 0 2 can be paired with Speakers / microphones 3 6 0 (4 2 2 in this figure) are paired. The part of the audio output of the speaker / microphone 4 2 0 is entered into the microphone 4 0-, which converts it into an electric signal. Similarly, a portion of the audio output of the speaker / microphone 4 2 2 enters the microphone 4 0 2, which is converted into an electric signal. Since the two microphones have opposite phases, these transformations come from the audio inputs of the speakers / microphones 4 2 0, 4 2 2 (respectively), and the resulting electrical signals are approximately in phase. The difference amplifier 408 then roughly removes the common-mode signal. Due to the relationship between the converter outputs, the configuration of the microphone and speaker / microphone is an important aspect of this design. A speaker / microphone 4 2 0 (Please read the notes on the back before filling out this page) The size of the paper is applicable to China National Standard (CNS) A4 (210X297 mm) -37-Staff of the Central Bureau of Standards, Ministry of Economic Affairs Printed by the consumer cooperative A7 B7_ 5. The description of the invention (35) and its associated microphone 40 0 should be placed in the same direction. Also, each pair of speakers / microphones and microphones should be facing away. This is shown in Fig. 9, where converters 400 and 420 point in the same direction, converters 40 2 and 422 point in the same direction, and two pairs of 400, 420 and 4 0 2, 4 2, 2 point in opposite directions. This configuration can isolate the output of the dual-purpose converter 4 2 0 and the microphone 4 02, and the output of the dual-purpose converter 4 2 2 and the microphone 400. One that meets this criterion may be configured as a box with converters 400, 420 in an up-down relationship, facing one side of the box, and converters 402, 4 2 2 in a similar up-down relationship, facing the other side of the box . Of course, there are other possible configurations to achieve acceptable results. It should be kept in mind that the purpose of this design is to increase the Tx signal with additional inputs, while providing a configuration that substantially removes any unwanted inputs. In order to achieve an increase in the Tx signal, the circuit includes a sum amplifier 130, which adds the T X signal provided by the circuit of FIG. 9 to the T X signal generated by another part of the circuit. For example, the Tx signal from the difference amplifier 370 in FIG. 8 may be added to the Tx signal generated at the output terminal of the difference amplifier 408 in FIG. This method can also be used for other speakerphone devices based on the circuit design shown in Figure 4. Although I have described the implementation of the invention in detail, it should be noted that the scope of the invention is not limited to these specific implementations. Full-duplex communication circuits can be implemented using many different combinations of the innovative circuit components described above. For example, the circuit used to apply the received signal to the converter without loading it can be combined with the circuit used to simultaneously compress the received signal and expand the transmitted signal in a variety of ways. Although this paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) ^ 8- '(Please read the precautions on the back before filling this page)-Order printed by the Consumer Standards Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs Explanation of the invention (36) The use of different configurations in combination with a compression-expander can improve performance and more effectively eliminate received signals, but if TX and RX signals are closer together, these components need not be used together. For example, a full-duplex converter can be connected to a circuit that simultaneously suppresses the received signal and expands the transmitted signal, without using an amplifier on the input stage to avoid loading the converter. However, by reducing the load to a minimum to avoid loss of the transmitted signal, better performance can be achieved, as described above. Telephone line interconnection circuit The main application of the above full-duplex communication circuit is the telephone industry. When used in a telephone device, these full-duplex communication circuits are used as a converter interface and connected to the telephone line via a telephone line interconnection circuit. The circuit shown above is called the converter interface because these converters are driven by the R X signal to generate audio output, and the converter is used to convert the audio input to the T X signal. Another circuit called a telephone line interconnection circuit is used to connect the Tx and Rx signals from the converter interface to the telephone line. Figures 10 and 11 show another implementation of the telephone interconnection circuit. 1 Figure 10 is the essential diagram of the telephone interconnection circuit 5 0 0, which uses a bilateral T-splice configuration. The telephone interconnection circuit transmits the τ X signal from the converter interface to the telephone line 502, and transfers the Rx signal from the telephone line 502 to the converter interface. The R X input and TX output of the converter interface are respectively connected to TX input 5 0 and R X output 5 0 of the telephone interconnection circuit. T generated in the interface of the converter; X signals are interconnected via telephone lines

I circuit is transferred to the telephone line. On the contrary, the R X signal from the telephone line passes the phone. The paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -39--(谙 Read the precautions on the back before filling this page)

A7 __B7_ 5. Description of the invention (37) The line interconnection circuit is transferred to the converter interface. As shown in Figure 10, the analog telephone line is connected to the telephone line interconnection circuit 500 through the telephone line interface. This interface includes a common hook switch 5 1 0 'inductor 5 1 2 a — b, filter 5 1 4a — b' rectifier 5 1 6, current regulator 5 1 8, light, coupler 5 2 0, isolation transformer 522, and capacitor 524. The filters 514a-b each include a capacitor connected between the signal path and the ground to filter the high frequency (R F) portion of the telephone signal. The bridge rectifier 5 1 6 receives the filtered telephone signal and provides a consistent polarity to the current regulator 5 1 8. This ensures that the circuit works with the sharp ring reversed. Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page) as "analog inductors". The voice signal can be transferred to the transformer 5 2 2. Due to the change in line length, the radio waves in the telephone line will fluctuate and sometimes fall too low. To cope with this problem, the analog inductor adjusts the load resistance of the telephone line to maintain a satisfactory loop current. The positive terminal of the rectifier 5 1 6 is connected to the collector of a resistor 5 3 0 and a bipolar transistor 5 3 2. The transistor's base is connected to a resistor and an AC shunt capacitor 534 (e.g., 10aF). The emitter of the transistor is connected to a voltage divider composed of two resistors 5 3 6-5 3 8. The voltage signal at the node between the resistors of the voltage divider is applied to the input of the optical isolator 5 2 0. The analog inductor uses an AC shunt capacitor 5 3 4 to ensure that almost all telephone signals are transferred to the isolation transformer 5 2 2. The isolation transformer in the interconnection circuit is used as a repeater for telephone signals. this

I is a standard transformer used in telephone equipment and complies with F C C regulations. This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -40-A7 B7 V. Description of the invention (38) This has an input impedance of about 600 ohms and an output impedance of about 900 ohms. The Tx signal transferred by the magnetic cross-connection of the transformer coil's isolation transformer is transferred to the telephone line, and the incoming X signal is transferred to the RX circuit in the telephone interconnection circuit. To avoid feedback or bellowing, when connected to the telephone line, the loop gain of the feedback path in the R x and D X signal circuits must be less than one. When the hook switch is opened by operating a switch (F E T 540), the telephone line interface circuit ensures that the loop gain remains below 1, and when the hook switch is turned on, the transmission circuit is turned on. The transmission circuit includes-an automatic level controller (ALC) 543, a passband filter 544, a Tx amplifier 546 'and a Tx level adjuster 548 ° ALC, a passband filter, a FET' and a Tx amplifier via a capacitor 5 5 0 — 5 5 6 interconnected. When the LED 560 in the optocoupler is activated, this induces a signal in the optoelectronic crystal 562. A bipolar transistor 5 6 4 acts as a switch, which turns on the lamp 5 6 6 and drives the gate of the FET switch 5 4 0 via an RC network 5 6 8. Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling this page) When the telephone line interconnection circuit is interrupted by opening the hook switch (on / off switch) or if the telephone line is actually interrupted, optical coupling The device (which drives its LED current from the telephone line) causes the FET540 to provide an open circuit in the Rx / Tx feedback path. This open circuit prevents howling when the hook switch is turned off. When the telephone line current flows through 丄 E D, F E T 5 4 0 has a low resistance and completes a closed loop with a total gain below one. The telephone line interface and the transmission circuit are connected in a circuit arrangement, called a double-sided τ splicing circuit 570. Bilateral T-splice circuit provides bi-directional current flow to this paper. Applicable Chinese National Standard (CNS) A4 specification (210 X 297 mm) -41-A7 B7 V. Description of invention (39) Telephone line, such as by double arrow 5 7 2 And 5 7 4 marked. Specifically, the telephone signal enters the bilateral T circuit through the isolation transformer 5 2 2, and the signal is transmitted to the bilateral T circuit through the amplifier A 1 due to the current mirror effect of the amplifier A 1. In this way, the reception signal from the telephone line and the transmission signal from the transmission circuit are combined at the bilateral T-splice circuit, with the T connectors 5 7 6. The bilateral T-splicing circuit shown in FIG. 10 includes amplifiers A1 and A2 (578, 58 0), each of which is a negative input terminal of an ordinary operational amplifier operational amplifier A 1 connected to a positive input terminal of the operational amplifier A 2. An AC circuit 5 8 2 is connected between the output node of A 1 and the ground to compensate for the phase shift caused by the isolation transformer 5 2 2 and the reactive components in the telephone line. To ensure A 1 and A 2 balance, the gain of A 2 is adjusted by a variable resistor 5 8 4 and connected between the output and negative input of A 2 ... Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please first Read the notes on the back and fill in this page again.) The Tx signal from the TX amplifier 5 4 6 is fed to the 疋 (non-inverting) input of A 1 via the capacitor 5 8 4. Through the current mirror of A 1, a T X signal which is the same as the T X signal on the positive input terminal of A 1 appears on the negative (inverted) input terminal of A 1. The Tx signal on the negative input terminal of A 1 is fed to the positive input terminals of the isolated calendar 5 22 and A2. A1 and A 2 generate an output T X signal, which has the same polarity and is common mode. As such, these can be eliminated by using a subtraction amplifier 590 subtraction, as shown in FIG. 10. Because of the virtual ground on the negative input of A 1, the positive ground of A 2 sees the virtual ground of A 1. Due to this virtual ground, the Rx signal coming from the transformer 5 2 2 appears only on the output ridge of A 1. In this way, the RX signal at the input of the difference amplifier does not appear as a common mode, and the paper standard of the difference amplifier applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -42-A7 __'_ B7__ 5. Description of the Invention There is no cancellation of the RX signal at the output of (40) 590. When the telephone signal is small, a compressor as shown in Figure 12 can be used to improve the separation between the Tx and Rx signals. In this configuration, a resistor can be inserted between node 5 7 6 and the inverting terminal of A 1, and the 11 X signal at each input terminal of the difference amplifier is out of phase by 18,0 degrees. The difference amplifier amplifies the R.X signals and, therefore, provides a larger Rx signal at its output. The difference amplifier 590 of FIG. 10 is implemented by a common operational amplifier. The output of A 2 is connected to the negative input terminal of the operational amplifier 5 9 0 via a capacitor 5 9 2 and a resistor 5 9 4. The output of A 1 is connected to the positive input of the operational amplifier 5 9 0 via the RC network 5 8 2 and another resistor 5 9 6. In the configuration of the difference amplifier, a first resistor 598 is connected between the output terminal and the negative input terminal of the operational amplifier 590, and a second resistor 608 is connected to the positive input terminal of the operational amplifier. Between the ground. These resistors have approximately equal resistance settings. Printed by the Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs (Read the notes on the back and then fill out this page) By eliminating common mode Tx signals and passing Rx signals, the bilateral T-splicing circuit effectively separates T X signals and R X signals. To provide further separation, the telephone interconnection circuit includes an expansion-compression circuit 602, which is connected to the output of the difference amplifier via a capacitor 604. The expansion-compressor expands the larger Rx signal and the smaller-compressed Tx signal in the same manner as the expander IC in the output stage shown in FIG. 4 (compression-expander 16 4 in FIG. 4). Figure 11 is a schematic diagram showing another telephone line interconnection circuit. This uses a balanced impedance configuration. The earphone circuit of the telephone line in Fig. 1 uses the same (or similar) telephone interface and transmission circuit as shown in Fig. 10, so the telephone connection is based on the Chinese National Standard (CNS) A4 specification (210X297 mm) -43 -Printed by A7 ____B7_ of the Consumer Cooperatives of the Central Procurement Bureau of the Ministry of Economic Affairs. 5. Description of the Invention (41) These parts of the circuit are omitted in Figure 11. The balanced impedance configuration of FIG. 11 includes two operational amplifiers 6 2 0 and 6 2 2 whose positive ends are connected together at a common node 6 2 4. The operational amplifiers are each arranged in a voltage feed current feedback configuration. In other words, each amplifier feeds a voltage signal and generates a current output signal, which is fed back to the input terminal of the amplifier via a feedback path. This configuration provides a high source impedance to the transformer, so there is approximately no load on the transformer. This can amplify the small received signal ' without load loss. The first operational amplifier 6 2 0 feeds a current output back to the isolation transformer 6 2 6 and a shunt resistor 6 2 8 is connected across the two ends of the transformer. The other operational amplifier 6 2 2 feeds a current output and returns it through another transformer 6 3.0 connected to an RC network 6 3 2 to simulate the impedance of the telephone line. The negative terminal of each operational amplifier is grounded through a resistor 634, 636. One of these resistors is variable to balance the output of the two operational amplifiers. The common node connected to the positive terminal of the operational amplifier passes another resistor 638. Ground. The T X signal from the T X amplifier is fed to the common node 6 2 4 through a capacitor 6 40 and an input voltage signal is provided to the positive terminals of each operational amplifier 620, 622. In response to this input Tx signal, the operational amplifier generates a TX output signal, which appears as a common mode on its output. The degree to which the two TX output signals match depends on the degree of impedance balance of the amplifier configuration. The common-mode Tx signal is cancelled by the subtraction effect in the difference amplifier 650. In contrast to the TX signal, the R x signal does not appear in common mode

I, so it is not cancelled in the difference amplifier. Operational amplifier I—-I 1 .----) connected to the isolation transformer .--------- Order ----- 0J (Read the precautions on the back before filling this page) Paper size applies Chinese National Standard (CNS) A4 specification (210X297 mm) -44-A7 B7 V. Description of the invention (42) The device 6 2 0 receives the Rx signal from the telephone line and the Tx signal from the τχ amplifier and generates One combined TX and RX signal. The R signal from the telephone line circuit is fed to the negative terminal of this operational amplifier 620. The output of the operational amplifier 6 2 0 is a combined Tχ and R X signal, which is fed to the positive input of the difference amplifier 6, 50, and is also inverted; fed to the telephone line interface. Since no Rx signal is input to another operational amplifier 6 2 2, there is no R X signal portion at its output, nor is it at the negative input of the difference amplifier 650. Therefore, the difference amplifier passes the Rx signal to its output. Printed by the Consumers' Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs (Please read the notes on the back of the page before filling out this page) As mentioned above, the difference amplifier 6 50 in Figure 11 eliminates the common-mode TX signal and passes the R x signal. The difference amplifier 6 5 0 includes a common operational amplifier 6 5 2, resistors 6 5 4, 6 5 6 are connected to the positive and negative input terminals of the operational amplifier, and a resistor 6 5 8 is connected to the negative input terminal of the operational amplifier to the output terminal. , And another resistor 660 is connected to the positive input terminal of the operational amplifier to ground. The difference amplifier 6 50 receives the Tx and Rx signals from the combination of the operational amplifier 6 2 0 through a capacitor 6 6 2 and a resistor 6 5 6. This receives the T X signal from the operational amplifier 6 2 2 via another capacitor 6 6 4. The difference amplifier substantially eliminates the Tx signal and generates an Rx signal. Through a capacitor 6 68 connected to the output terminal of the operational amplifier 6 5 2 °, for the telephone interconnection circuit of FIG. 10, the balanced impedance configuration is more accurately simulated. The receiving part of the telephone line. As a result, the T X signal output from the operational amplifier is more uniformly matched. This allows the difference amplifier to improve the cancellation of the T X signal at its output. Note that if the difference amplifier sufficiently eliminates the T X signal, i has no expansion-compression circuit on the output of the telephone interconnection circuit. This paper size applies to China National Standard (CNS) A4 (210X 297 mm) -45-Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 __ 5. Description of the invention (43) Use bilateral T-splicing in the converter interface Circuit and balanced impedance configuration The bilateral T-splice circuit of Figure 10 and the balanced impedance configuration of Figure 11 can also be used in the converter interface, providing a combined TX / RX signal at the converter while still maintaining the telephone The wires are mutually connected, and the TX and RX signals at the Tx and Rx terminals of the circuit are separated. These two configurations provide a two-way signal path to the combined Tx and Rx signals at one end, while keeping the T X and R X signals at the other ends separated. In the telephone interconnection circuit, the two-way signal path is at the telephone line interface, and the purpose of the interconnection is to separate the T X signal sent to the telephone line from the R x signal received from the telephone line. In the converter interface, the two-way signal path is at the converter (this is used as a speaker / headphone and microphone), and the purpose of the interface is to separate the Tx signal generated in the converter and the Rx signal driving the converter . Bilateral T-splice configuration in the converter interface Figure 12 shows the schematic of a converter interface using one of the bilateral T-splice circuits. The two-sided T-splice circuit is connected to a converter, and the converter is used as both an input converter and an output converter. This provides bidirectional current flow to and from the converter and separates the Rx and Tx signals. The bilateral τ splicing circuit 680 in the converter interface shown in FIG. 12 is the same as the bilateral T splicing circuit shown in FIG. 10. However, in the application of the two-sided T-splicing circuit, the common node between the amplifiers A 1 and A 2 6 8 2 is connected to a converter, which is used as a full-duplex, audio output

• I input / audio device. Clearly stated, 'This converter can also be used as a microphone. The paper size is applicable to China National Standard (Yi Bi) 8 4 specifications (210 \ 297 mm)-(#Read the precautions on the back before filling this page ), Ordered-printed by A7 _ B7_____ of the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the Invention (44)-Speaker 6 8 4 or also used as one of the earphones of the microphone. The two-way current flowing on this T connector represents the combined R X signal, which is converted into audio output and the incoming Tx signal, which is generated by the audio input. The converter interface shown in Figure 12 receives the ~ Rx signal at the input node 690 as an input. The Rx input, the signal passes the capacitor 6 9 2, which filters out the low frequency part, and then to an automatic level controller 6 9 4, which controls the level of the input signal via a variable resistor 6 9 6. The output of the automatic level controller 6 9 4 is implemented by another variable level controller 6 9 8. The received signal is then fed to the positive input of amplifier A 1 of the two-sided T-splice circuit via a capacitor 700. The role of the bilateral T-splice circuit in the converter interface is similar to that of the telephone interconnection circuit described above with reference to FIG. 10. The only difference is that the incoming signal is an Rx signal instead of a Tx signal. Due to the current mirror of the amplifier A 1, a current signal on the positive input terminal of A 1 that is the same as the R X signal appears on the negative input terminal of A 1. This R X signal is then fed to a converter 6 8 4, which transforms it into an audio output signal. The R'X signal outputs of A 1 and A 2 have the same polarity and approximately common mode. In this way, the R X signals from A 1 and A 2 can be cancelled by the subtraction effect using a difference amplifier. Due to the virtual ground on the negative input of A 1, the Tx signal generated by the converter (6 8 4 or 6 8 6) is only presented on the output of A 1 because the positive input of A 2 is only See the virtual ground of A 1. In this way, the Tx signal output from the bilateral T-splicing circuit 680 has no common mode, and the Tx signal is not eliminated in the difference amplification 14. i The rest of the converter interface shown in Figure 12 and the converter shown in Figure 4 --- ^ ----------) ----- 1T ------- ( Please read the notes on the back before filling in this page) This paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -47-A7 ______ B7 ___ 5. Description of the invention (45) Node A and interface The circuit on the right of B is similar. As with the converter interface of Figure 4, the outputs of amplifiers A1 and A2 are connected to compression-expanders 710,712. Implemented by a common expander 1C, the compression-expander configuration reduces the R X signals from the amplifiers A 1 and A 2. A dilator 7 1 0 connected to the amplifier A 1 receives the combined Tx and Rx signals, and expands the smaller Tx signals while reducing the larger Rx signals. The difference amplifier configuration 7 1 4 receives the output from the compression-expander 7 1 0, 7 1 2 and eliminates the common-mode Rx signal while passing the Tx signal. The output of the difference amplifier_7 1 4 is then transferred to another compression-expander 7 1 6 via a one-bit regulator 7 1 8. The compression-expander 7 1 6 is different in FIG. 12 because its configuration is increasing the current larger Tx signal and decreasing the smaller R X signal at the same time. This produces a T X output signal, where the Rx signal portion is almost completely removed. Note that in Fig. 12, contrary to Fig. 4, the compressor_expander 7 1 0, 7 1 2, the difference amplifier 7 1 4, and the expander-compressor 7 1 6 via the capacitor 7 2 0 — Central Bureau of Standards, Ministry of Economic Affairs Employee Consumer Cooperative Printed 7 2 8 Connected Together. Further, a dilator-compressor 7 1 6 is also connected to a capacitor 7 3 0. Although not important to the present invention, these capacitors can improve performance by filtering out the D C portion of the T X and R X signals. Balanced impedance configuration in converter interface Figure 13 is a schematic diagram showing a converter interface, which uses a balanced impedance configuration. Rather than balancing the impedance of the telephone line as shown in Figure 11, the balanced impedance configuration in the interface of the converter is used to balance the impedance of one of the converters as an input and output device. Depending on the application, this converter can be a speaker 7 50, -48- (谙 first read the notes on the back and then fill out this page) This paper size applies to China National Standard (CNS) A4 specifications (210X297 mm) A7 B7 5. Description of the invention (46) 752, or headphone 754, 756. In the balanced impedance configuration shown in Fig. 13, the impedance of one converter is matched using the same converter. Note It is also possible to replace a matched converter (such as speaker 752) with an RC (or RLC) profile to balance the impedance of the converter (such as speaker 750). ... Like the balanced impedance configuration in Figure 1 and Figure 1, one of the configurations used in the converter interface of Figure 13 includes two operational amplifiers. 7 6 0, 7 6 2, whose positive ends are at the common node 7 6 4 Connected together. The current mirror bias of the operational amplifiers 7 6 0, 7 6 2 acts as a current source. This generates an Rx signal at the negative input of the operational amplifier 7 6 0, 7 6 2, which is the same as the Rx signal at the positive input. Operational amplifiers 7 6 0, 7 6 2 receive Rx signals on their positive inputs and drive the RX signals through their negative inputs into a converter (printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (read first, read on the back of the reader). Note: Please fill in this page again) 7 50, 7, 5 2). The negative input is at virtual ground, meaning that its potential to ground is approximately zero. The operational amplifiers each have a first resistor 7 6 6, 7 7 0 (such as R 1) connected between its output terminal and its negative terminal, and a second resistor 7 6 8, 7 7 2 (such as R 2 ) Is connected between its negative terminal and ground. The second resistor is connected across the converter 750, 752 to reduce the Q of the converter. This resistor reduces the interference of the harmonic frequency (ie, reduces the interference of the harmonic frequency). Because the virtual ground cannot sink current, all input current from the RX signal at the operational amplifier 760 is forced through resistors R 1 and R2 766,768 and converter 750 »Another amplifier in a balanced impedance configuration 7 6 2 has the same effect, the converter (7 5 2) is connected with its opposite polarity to the converter (752). This paper size applies to China National Standard (CNS) A4 (2 丨 0 X 297 mm) -49-Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 ___'_ B7 V. Description of the invention (47) Operational amplifiers 760,762 Generate a common-mode Rx signal. As such, the common-mode R X signal can be removed by subtraction in a two-difference amplifier. In the converter interface shown in Figure 13, the Rx signal enters the converter interface at the input port 7 800 and passes a capacitor 7 8 2, an automatic level control 罨 7 8 4 and a level adjustment.器 7 8 6. Automatic level The controller adjusts the level of the signal via a variable resistor 7 8 8. The circuit between input port 7 8 0 and node 7 6 4 is similar to the circuit at the positive input terminal of A 1 in Fig. 12, and therefore, its function description is not repeated here, because the converter 7 5 0, 7 5 2 is connected with opposite polarity, so the RX signal generated by it has opposite polarity. The Tx signals at the output terminals of the operational amplifiers 7 6 0, 76 2 also have opposite polarities. Therefore, the TX signal can be combined in a difference amplifier to increase the TX signal generated in the converter. The converter interface circuit 790 shown in Fig. 13 is similar to the circuit shown in the converter interface of Fig. 12, and therefore, its description is not repeated here. Converter interface using a piezoelectric converter Figure 14 is a schematic diagram showing a converter interface using another balanced impedance configuration. This configuration uses high impedance amplifiers 800, 802 to drive the converters 804, 806 in a balanced configuration. The configuration of the converter in FIG. 14 receives the incoming R X signal through an input circuit 8 0 8. This input circuit is similar to the input circuits shown in FIGS. 12 and 13. Moreover, the circuit 810 at the output of the amplifiers 800, 802 is similar to the circuit at the output of the amplifiers in Figs. Therefore, input and input (Notes on the back of Min Xianmin, and then fill out this page) The size of the paper is applicable to the Chinese National Standard (CNS) Α4 specification (210 X 297 mm) -50 Employee consumption cooperation of the Central Standards Bureau of the Ministry of Economic Affairs Du printed A7 _B7____ V. Description of the invention (48) Circuits 808, 810 are not repeated here. The converter interface of Fig. 14 has a balanced impedance configuration 'because it has the same converters 8 0 4 and 8 0 6 each connected to-amplifiers 8 0 and 8 2. Different from the balanced configuration of Fig. 13, these converters are connected between the output of the operational amplifiers 800, 802, and the negative input. This particular configuration design uses a piezoelectric transducer. Specifically, the implementation shown here is specifically designed for use with piezoelectric headphones, which has the dual function of generating a transmission signal from an audio input and converting a received signal into an audio output. The reactive components of some converters can adversely affect the frequency response of the amplifier in the frequency range where speech is generally reduced. Piezoelectric transducers provide higher performance for speech applications because the reactive components of the transducer have little or no effect on the frequency response of the amplifier. In this implementation, the piezoelectric converter is a quartz converter. Quartz converters are advantageous because they have the same impedance, which makes it easy to match the impedance of each converter. The amplifiers 8 0, 8 0 2 have very high output impedance, which enables them to drive the converters 8 0, 8 0 6 with minimal or no load. The gain of the amplifier in this implementation should be set to 1 by selecting resistors R 1 and R 2 with equal resistance. Moreover, the gains of the amplifiers 800 and 802 are matched, so the difference amplifier connected to the output of the amplifier substantially eliminates the common-mode portion generated by the amplifiers 800, 802. The amplifiers 800, 802 receive the Rx signal as an input, and convert these signals into a common mode at their outputs. To be clear. The R X signal enters the positive terminal of each amplifier via a resistor 8 2 0 ′ 8 2 2. The amplifier i is configured as a voltage-to-current converter. The paper size of each amplifier is applicable to Zhongguanjia Standard (CNS) Eighty-fourth Secret (210X297 Gonglu): 51-:: J ... IT. (Please read the notes on the back before filling this page) Central Ministry of Economic Affairs Printed by A7 B7 of the Consumer Cooperatives of the Bureau of Standards. 5. The current output (including the received signal) of the invention description (49) is fed to the positive end of each converter 804,806. The converter converts the received signal into an audio output. The converter also functions as a microphone, transforming the audio input into a TX signal. As a result, the combined T X and R X signals appear at the output terminals of 800, 802 per amplifier. The Tx signal part of the output of the amplifier 8 0.0, 8. 0 2 has opposite polarity. As such, when applied to a difference amplifier, the T X signals are added. Conversely, the received signals at the output of the amplifier have the same polarity, and therefore, the difference amplifier substantially eliminates the Rx signal portion. The full-duplex circuit described above can be used to provide a 2-wire bidirectional signal path and a separate 2-wire unidirectional signal path. In a telephone device, a full-duplex circuit can be used as a 2-wire to 4-wire circuit at the converter and as a 4-wire to 2-wire circuit at the telephone line. 4-wire to 2-wire circuits need to be used in devices that are not equipped with 2-wire bidirectional transmission media, such as telephone lines. For example, cell phone devices send and receive signals on separate signal paths. This aspect of the cellular telephone can cause feedthrough problems when a 4-wire device, such as a cellular telephone, communicates with a 2-wire device, such as a normal telephone. If the telephone has a common split circuit, the split circuit may exhibit a phenomenon called loss of rotation. Slewing loss is a characteristic of lossy splicing circuits, where the signal "misses" the splicing circuit. For example, instead of the incoming R X signal being separated from the outgoing T X signal, a lossy splicing circuit will leak back a portion of the R X signal to the telephone line. Moreover, the lossy splicing circuit will miss a portion of the T X signal back to the R X signal path in the telephone. * A 4-wire device that communicates with a 2-wire g device with a lossy split circuit needs to cope with the rotation loss from the 2-wire device. The paper size of the signal sent to the 2-wire device applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -52: " ~~ —; —------. · .------ -Order ------ (Please read the precautions on the back before filling this page) Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs Α7 Β7 V. Description of the invention (50) Partially missed the splicing circuit and return To 4-wire installation. This can be addressed in several ways. One method is to connect a comparator between the R X and T X signal paths in the 4-wire device to detect the T X signal sent by the 4-wire device and feed it back to the R X part of the 4-wire device. According to the degree of similarity between the T X and R X signals in the 4-wire device, the comparator can start a fader and subtractor to reduce the R X signal v and thereby reduce the effect of feedback to the R X side due to the rotation of the lossy composite circuit. λ Another method is to use an adaptive filter in, for example, a normal full-duplex speakerphone .. Unlike the above-mentioned speakerphone device, the ordinary speakerphone device has a separate microphone and a speaker. These devices need to deal with acoustic feedback and the aforementioned loss of rotation. To cope with this kind of feedback, an ordinary speakerphone uses an adaptive filter, as described in US Patent Nos. 4, 6 2 9 and 8 2 9. • This column is for reference. The adaptive filter takes the τ X signal as an input and simulates the feedback of the TX signal 1 to the R X port of the device. The analog feedback signal can then be subtracted from the R X signal. A similar method can be used in a 4-wire device to ..... · Λ deal with the loss of rotation of a lossy split circuit. Conclusion_ Although I have described the implementation of the present invention in detail, it should be noted that the scope of the present invention is not limited to these specific implementations. Since the principles of the present invention can be applied to many embodiments, it should be understood that the embodiments shown are merely examples of the invention and should not be taken as limiting the scope of the invention. Instead, the scope of the present invention is defined by the following patent applications. Therefore, all the inventions within the scope and spirit of these patent applications are included in this application. First read the notes on the back and then fill out this page) This paper size applies to Chinese National Standard (CNS) Α4 size (210X297 mm) -53-A7 B7 ). .— ： ---.—--------- 1T ------ 0, (Read the notes on the back first and then fill out this page) This paper size applies to Chinese National Standards (CNS ) A4 size (210X297 mm) -54-

Claims (1)

Printed by the Consumer Standards Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A8 B8 C8 D8 VI. Patent application scope 1 full-duplex audio communication circuit, including: a first converter for converting audio input into electrical transmission signals, and for converting The electrical reception signal representing audio data is audio overrun; and an expansion-compression circuit in communication with the first converter for receiving a combined signal including a transmission signal and a reception signal, and for simultaneously expanding the transmission signal and compression reception Signal to generate an output signal, where the transmitted signal is at least 10 times larger than the received signal. 2. The circuit according to item 1 of the scope of patent application, comprising:-a matching impedance device that matches the impedance of the first converter, wherein the matching impedance device receives the received signal;-a compression circuit connected to the matching impedance device and To receive the received signal and compress the received signal;-a difference amplifier connected to the expansion-compression circuit and the compression circuit to receive the combined signal from the expansion-compression circuit and the received signal from the compression circuit to combine the expansion signal -The combined signal of the compression circuit and the received signal from the compression circuit, the received signal is roughly canceled. 3. The circuit according to item 2 of the scope of patent application, wherein the matching impedance is a second converter for converting an audio input into a second electrical transmission signal and for converting an electrical receiving signal into an audio output; The compression circuit is part of a second expansion-compression circuit, and the second expansion-compressor is connected to the second converter for receiving a combined signal, including a second sending and receiving signal, for simultaneously Expanding the second transmitting signal and compressing the receiving signal; and wherein, the difference amplifier is connected to the second expanding-compression circuit for applying the Chinese National Standard (CNS) A4 specification (210X297 mm) to this paper size 55---Ί. —-^ ----------- Order ------_-- (Please read the precautions on the back before filling out this page) Printed by the Staff Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs The scope of the patent application adds the first and second transmission signals together and cancels the received signals at the same time. 4. The circuit according to item 3 of the scope of patent application, further comprising: a second difference amplifier having first and second input terminals; a first microphone connected to the first input of the second difference amplifier The first microphone is configured to receive the first audio input, including at least a portion of the voice input and the audio output from the first converter, and wherein the first microphone can function to transform the first audio input. An audio input is a first electrical signal; a second microphone is of opposite polarity to the first microphone, and the second microphone is connected to a second input terminal of a second difference amplifier, wherein the second The microphone is configured to receive the second audio input, including at least a part of the voice input and the audio output from the second converter, and the audio output from the first converter received in the first microphone It is about the same as that received in the second microphone. The audio output from the second converter is about 180 degrees out of phase ', and the second microphone can function to transform the second audio input into the first. Two electrical signals, and among them, the second difference amplifier makes The electrical signal caused by the voice input is approximately doubled, and the common mode signal caused by the audio output of the first and second converters is substantially eliminated; and)-the amplifier is connected to the output ends of the first and second difference amplifiers, Used to combine the output signals from the first and second difference amplifiers. .5. The circuit according to item 1 of the scope of the patent application, wherein the first converter is connected to a linear amplifier for transferring the received signal to the converter ′ without adding a load to the converter. This paper applies the Zhongguanjia Standard (CNS) A4 (21GXW7 mm).-56-(Please read the precautions on the back before filling out this page) Α8 Β8 C8 D8 Price: Apply for a patent scope 6. If you apply for a patent The circuit of item 5, wherein the linear amplifier includes an operational amplifier having a non-inverting input terminal and an inverting input terminal; and wherein the non-inverting input terminal receives the receiving signal, and the inverting input terminal is connected to The first converter, and wherein the amplifier feeds the received signal to the inverting input terminal of the converter without loading the converter. 7. The circuit described in item 1 of the scope of the patent application, further comprising a bipolar transistor for driving the converter by the received signal and amplifying the transmission signal generated in the converter. 8. The circuit according to item 7 in the scope of the patent application, wherein the transistor has an electrode, a collector, and an emitter; and wherein the base receives the received signal; and wherein the converter is connected to the emitter, And a matched impedance device is connected to the collector. 9. The circuit as described in item 8 of the scope of patent application, further comprising: an inverter connected to the collector;-an amplifier connected to the output of the converter between the converter and the expansion-compression circuit. Printed by the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page). A compression circuit connected to the inverter to compress the received signal: and a differential amplifier connected to the expansion- A compression circuit and a compression circuit for receiving a combined signal from the expansion-compression circuit and a reception signal from the compression circuit for combining the combined signal from the expansion-compression circuit and a reception signal from the compression circuit to receive The signal is roughly canceled. 10. The circuit as described in item 9 of the scope of patent application, wherein the paper size applies to the Chinese National Standard (CNS) A4 specification (210X297 mm) -57-A8 B8 C8 D8 A part of a first expansion-compression circuit for compressing a reception signal and expanding a transmission signal at the same time; and wherein the difference amplifier is connected to the expansion-compression circuit and a second expansion-compression circuit for adding the transmission signals , And cancel the received signal. 1 1. The circuit described in item 1 of the scope of patent application, further comprising:-an output stage for receiving an output signal that expands a compression circuit, and for simultaneously expanding a transmission signal and compressing a received signal. 12. The circuit according to item 1 of the scope of patent application, wherein the first converter is driven by the received signal without being loaded on the first converter. 1 3 · The circuit described in item 1 of the scope of patent application, wherein the first converter is driven by the received signal without shunting the first converter. 1 4. A full-duplex audio communication circuit for generating audio output and transmitting audio input at the same time, the circuit includes:-a first converter for converting an audio input into an electrical transmission signal, and for converting audio data representatively x The electric receiving signal is audio output; and printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page) — audio processing circuit, connected to the first converter, to receive a combination The signal includes a transmission signal and a reception signal, and is used to expand the transmission signal and compress the reception signal to generate an output transmission signal. The transmission signal and the reception signal are separated by at least 2 5 d B »1 5. The circuit described in item 4 further includes a second converter for converting an audio input into a second electrical transmission signal and an electrical receiving signal representing audio data into an audio output, wherein the first and second The converter has the opposite polarity, and the 'audio processing circuit contains: This paper size applies to China National Standard (CNS) A4 specification (210X2 97 mm) 58- 6. Patent application scope-a first difference amplifier for receiving a signal from a first converter and a signal from a second converter for a second converter, including The second transmission signal and the reception signal are used to substantially eliminate the reception signal, and simultaneously combine the transmission signals from the first and second converters. 16. The circuit according to item 14 of the scope of patent application, wherein the received signal is applied to the first and second converters, and an operational amplifier is used to reduce the load of the first and second converters to a minimum. 17. The circuit according to item 14 of the scope of patent application, further comprising a second differential amplifier having first and second input terminals; a first microphone connected to the first input of the second differential amplifier End, wherein the first microphone is configured to receive the first audio input, including at least a part of the voice input and the audio output from the first converter, and wherein the first microphone can function to Transform the first audio input into a first electrical signal; printed by the Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs (read the precautions on the back before filling out this page) a second microphone, which has a connection with the first microphone In the opposite polarity, the second microphone is connected to one of the second inputs of the second difference amplifier. The second microphone is configured to receive a second audio input, including a voice input and audio from a second converter. Output of at least In part, the audio output from the first converter received in the first microphone is about 180 degrees out of phase with the audio output received from the second converter in the second microphone. And, the second microphone can function to convert the second audio input into the second electric signal, and among them, the second difference amplifier makes the electric signal caused by the voice input about the paper standard applicable to the Chinese National Standard (CNS) A4 specifications (210X297 mm) 59-A8 B8 C8 __ D8 VI. Double the scope of patent application 'and substantially eliminate common mode signals caused by the audio output of the first and second converters. · And a and amplifier, connected to The output terminals of the first and second difference amplifiers are used to combine output signals from the first and second difference amplifiers. 1 8. A full-duplex audio communication circuit including: a converter for converting an audio input into an electrical transmission signal and an electrical receiving signal representing audio data into an audio output; a matching impedance device for matching conversion The impedance of the device is used to receive the received signal, and an expansion and compression circuit is connected to the first converter to receive a combined signal, including a transmission and a reception signal, to simultaneously expand the transmission signal and compress the reception signal; a compression Circuit, connected to the matching impedance device, used to receive the received signal, used to compress and shrink the received signal; printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling this page)-Difference amplifier Connected to the expansion-compression circuit and the compression circuit to receive the combined signal from the expansion-compression circuit and the received signal from the compression circuit 'to combine the signal from the expansion-compression circuit and the compression circuit from Received signal, the received signal is roughly canceled. 19. The circuit according to item 18 of the scope of patent application, wherein the matching impedance is a second converter for converting an audio input into a second electrical transmission signal, and for converting an electrical receiving signal into audio Output; wherein the compression circuit is part of a second expansion-compression circuit, and the second expansion-compressor is connected to the second converter for receiving a combined signal, including the second sending and receiving signals, In order to simultaneously expand the second sending of this paper, apply the Zhongguan Family Standard (CNX) (210X297 gong): 60-A8 B8 C8 D8 VI. Patent application range signal and compressed reception signal; and among them, the difference amplifier is connected to the second A compression circuit is expanded to add the first and second transmission signals together and cancel the received signals at the same time. 20. A full-duplex audio communication circuit comprising:-a converter for converting an audio input into an electrical transmission signal and an electrical receiving signal representing audio data into an audio output; and-an amplifier for transferring Receives signals to the converter without loading the converter. 2 1. The circuit according to item 20 of the scope of patent application, wherein the amplifier includes an operational amplifier having a non-inverting input terminal, an inverting input terminal, an output terminal, and a resistor connected to the inverting circuit. Between the input terminal and the output terminal; and wherein the non-inverting input terminal receives the received signal, wherein the inverting input terminal is connected to the converter, and wherein the amplifier feeds the received signal to the converter without adding a load to the conversion Device. • 2 2. The circuit as described in item 20 of the scope of patent application, wherein the amplifier includes an operational amplifier having a non-inverting input terminal and an inverting creep-in terminal; and an employee consumer cooperative of the Central Standards Bureau of the Ministry of Economic Affairs Printed (read the precautions on the back before filling this page) where the non-inverting input receives the received signal, where the inverting input is connected to the converter, and where the amplifier feeds the received signal to the converter without Load the converter. 2 3. The circuit according to item 20 of the scope of patent application, wherein the amplifier includes an operational amplifier having a non-inverting input terminal, an inverting input terminal, and an output terminal; and the paper size is applicable to the country of China Standard (CNS) A4 specification (210X297 mm) -61-A8 B8 C8 D8 6. The scope of patent application Among them, the non-inverting input terminal receives the received signal, wherein the converter is connected between the inverting input terminal and the output terminal, Moreover, the amplifier feeds the received signal to the converter without adding a load to the converter. 24. The circuit according to item 20 of the scope of the patent application, wherein the amplifier includes a bipolar junction transistor connected to a common emitter configuration, wherein the converter is connected to the emitter of the transistor, where The transistor receives the received signal on its base, and the transistor amplifies the received signal and applies the amplified received signal to the transponder without adding a load to the converter. 25 methods for performing full-duplex communication, the method uses a converter to convert an audio input into an electrical transmission signal and an electrical received signal representing audio data to an audio output; the method includes: applying reception The signal is transmitted to the converter without being negatively rotated on it; generating a combined signal on the output of the converter, including sending and receiving signals; and receiving the combined signal, and simultaneously expanding the combined signal Send signal and reduce receive signal. 26. The method as described in item 25 of the scope of patent application, including: Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling this page). The output of the converter includes sending and receiving signals; applying and receiving signals to a second converter without loading the second converter; generating a second combined signal to the second converter The output terminal includes a transmission signal and a reception signal, wherein the transmission signal from the second converter is out of phase with the transmission signal from the first converter; and this paper size applies the Chinese National Standard (CNS) A4 specification (210X297) (%) Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs. 6. The scope of the patent application reduces the signal from the combination of the first and second converters. The signal sent from each converter is approximately doubled, and The combined received signal is roughly canceled. 27. The method as described in item 25 of the scope of patent application, comprising: using a first set of converters to convert audio inputs into multiple electrical transmission signals, and converting electrical received signals representing audio data into multiple audio outputs The signal, wherein the signal at the output of each converter includes both the received and transmitted signals; and the signal combined at the output of the first group of converters. 28. The method according to item 27 of the scope of patent application, further comprising using a second set of converters to convert the audio input into a plurality of electrical transmission signals, and converting the electrical reception signal representing audio data into a plurality of audio output signals, Among them, the signals on the output end of the second group of converters each include both receiving and transmitting signals, and the transmitting signals are different from the transmitting signals generated by the first group of converters; The signal at the output of the converter; subtracts the combined signals from the first and second groups of converters, doubles the transmitted signals from each group, and roughly cancels the combined received signals. 2 9. A bilateral T-splicing circuit including: a first and a second operational amplifier each having a positive input terminal, a negative input terminal, and an output terminal, wherein the positive terminal of the second operational amplifier is connected to the first The negative end of the operational amplifier to form a T connector, and 'each paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -63-(Please read the precautions on the back before filling this page) 6. The output terminal of the patented operational amplifier is connected to the negative input terminal of the operational amplifier via a resistor; wherein, the positive terminal of the first operational amplifier can function to receive a first input signal. When an input signal is input, the first operational amplifier can function to generate approximately the same signal portion through the negative input terminal of the first operational amplifier to the T connector; wherein the first and second operational amplifiers are configured to generate a common-mode signal portion. It is equivalent to the first input signal at the output end of each operational amplifier. Among them, the first and second operational amplifiers can function to receive one second at the T connector. Input signal and generating an output signal at the output terminal portion, with the second input signal rather, these substantially similar amplitude and phase of the phase difference of about 180 degrees. '3 0. The circuit described in item 29 of the scope of patent application, including a difference amplifier, connected to the output, and can be used to eliminate the common mode part, and the phase difference is about 1 8 0 Degree of output signal. 31. The circuit as described in item 30 of the scope of patent application, further comprising a compression-expansion circuit connected to the difference amplifier. Printed by the Consumer Standards Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs (please read the notes on the back before filling out this page) 3 2. The circuit described in item 29 of the scope of patent application, in which the output of one of the operational amplifiers Connected to a matching impedance circuit to balance the impedance of the T connector. 33. The circuit according to item 29 of the scope of patent application, wherein the T connector is connected to a telephone interface circuit. 34 _ The circuit described in item 33 of the scope of patent application, wherein the telephone interface circuit includes: This k-sheet scale applies the Zhongguanjia Standard (CNS) Congxie (210X297 mm) 'A8 B8 C8 D8 VI. Application The patent scope proposes an inductive circuit to regulate the current from the telephone line. 35. The circuit as described in item 33 of the scope of patent application, wherein the telephone interface circuit comprises: an off-circuit, which can be connected to a telephone line to monitor the current from the cord: telephone line; and when the current drops 'Below a threshold or when it drops to zero,' actuate a switch to open the signal path of the transmitted signal. 36. The circuit according to item 35 of the scope of patent application, wherein the H-off circuit includes an optical coupler, which is actuated by the current from the telephone line. The circuit described includes:-Analog inductive circuit to regulate the current from the telephone line. 38. The circuit according to item 33 of the scope of patent application, wherein the T connector is connected to the telephone interface through an isolation transformer. 3 9 · The circuit as described in item 29 of the scope of patent application, wherein the input signal is a receiving signal and the second input signal is a transmitting signal printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read it first) Note on the back, please fill out this page again) 'And where' T connector is connected to a converter, which is used to convert the audio input into a send signal, and to convert the received signal representing audio data into an audio output. 40. The circuit as described in item 39 of the scope of patent application, wherein the output terminal is connected to a difference amplifier, which can function to eliminate the common mode part and the output with a phase difference of 180 degrees. Signal section. 41. The circuit according to item 39 of the scope of patent application, wherein each output terminal is connected to a compression-expansion circuit for increasing the transmission signal and decreasing the reception signal. This paper size applies to China National Standard (CNS) A4 (210X297 mm) -65-Printed by the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs Αδ Βδ C8 D8 VI. Application for patents 4 2 — A telephone line interconnection circuit, Including: first and second operational amplifiers each having a positive input terminal, a negative input terminal, and an output terminal, wherein the positive terminals of the first and second operational amplifiers are connected together, and wherein the first and second Two operational amplifiers can function, 俾 receive and transmit signals on the positive side, and generate a common-mode transmission signal on the output side. T An isolation transformer is connected across the negative input and output ends of the first operational amplifier. Among them, the isolation transformer It can function to transfer the sending signal from the first operational amplifier to the telephone line, and transfer the receiving signal from the telephone line to the first operational amplifier; An impedance circuit is connected across the negative input terminal and output of the second operational amplifier And can function to balance the impedance of the telephone line; and a difference amplifier connected to the output terminals of the first and second operational amplifiers, Differential amplifier may act to eliminate the common mode signal is sent, and by receiving the signal from the first operational amplifier. 43. The circuit according to item 42 of the scope of patent application, wherein the isolation transformer can function and is connected to the telephone line through a telephone interface circuit. 44. The circuit according to item 43 of the scope of patent application, wherein the telephone interface circuit comprises:-an analog inductive circuit for regulating the current from the telephone line. 45. The circuit according to item 43 of the scope of patent application, wherein the telephone interface circuit includes:-an isolation circuit that can be connected to the telephone line to monitor the current from the telephone line, and when the current drops to This paper applies the Chinese National Standard (CNS) (21GX297 mm) -66-when it is below the threshold or when it reaches zero: (Please read the precautions on the back before filling this page) ......... ..— ^ 1 I- II-i— *-> ^ i I--H · ϋ ϋ in I— 1 ------1 ......---Central Standard of the Ministry of Economic Affairs A8, B8, C8, D8 printed by the Bureau ’s Consumer Cooperative. 范围, the scope of patent application 'actuate a switch to open one of the signal paths for sending signals. 46. The circuit according to item 45 of the scope of patent application, wherein the isolation circuit includes an optical coupler, which is actuated by a current from a telephone line. 47. A full-duplex communication circuit with a balanced impedance structure, the circuit includes: a first and a second operational amplifier, each having a positive input terminal, a negative input terminal, and an output terminal, wherein the first and The positive ends of the second operational amplifier are connected together, and the first and second operational amplifiers can be used. The first input signal is received on the positive end, and the common mode signal corresponding to the first input signal is generated at the output. A bidirectional device connected across the negative input and output of the first operational amplifier; wherein the bidirectional device can function to receive a first input signal from the first operational amplifier and generate a first The input signal corresponds to one of the output signals; and wherein the inductive device can function to transfer one of the second input signals representing the incoming signal to the first operational amplifier; a matching impedance circuit is connected across the negative of the second operational amplifier The input and output terminals can be used to match the impedance of the bidirectional device; and a difference amplifier connected to the output terminals of the first and second operational amplifiers, the difference Amplifier may act to cancellation of common mode signals, and the corresponding one of the second input signal from the signal of the first operational amplifier. 48. The circuit according to item 47 of the scope of patent application, wherein the first input signal is a received signal and the second input signal is a transmitted signal, and wherein the bidirectional device includes a converter for converting The audio input is a sending signal, and the receiving signal used to convert the audio data is audio (please read the precautions on the back before filling this page), τ Γ This paper size applies to China National Standard (CNS) A4 specification (210X297) (67%) -67-Printed by the Consumers' Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs A8 B8 C8 D8 6. Application for patent park output. 49. The circuit according to item 48 of the scope of patent application, wherein the matching impedance includes a converter for converting an audio input into a transmitting signal, and for converting a receiving signal representing audio data into an audio output. . 50. The circuit as described in item 48 of the scope of the patent application, further comprising a first compression and expansion circuit connected between the output terminal of the first operational amplifier and the difference amplifier to increase the transmission signal and reduce the reception. signal. 51. The circuit according to item 47 of the scope of patent application, wherein the first input signal is a transmission signal and the second input signal is a reception signal representing audio data from a telephone line; and wherein the two-way device includes a transformer, It is used to transfer the transmission signal to the telephone line, and is used to transfer the reception signal from the telephone line to the first operational amplifier. 52. The circuit according to item 51 of the scope of patent application, wherein the transformer can function and is connected to the telephone line through a telephone interface circuit. 53. The circuit according to item 52 of the scope of patent application, wherein the telephone interface circuit includes an analog inductor for regulating the current from the telephone line. 54. The circuit as described in item 52 of the scope of patent application, wherein the telephone line interface circuit includes an isolation circuit which can be connected to the telephone line to monitor the current from the telephone line, and when the current drops When it is below a threshold or when it drops to zero, a switch is activated to open a signal path of the transmitted signal. 55. The circuit as described in item 47 of the scope of patent application, wherein the first input signal is a received signal and the second input signal is a transmitted letter. The paper size is applicable to China National Standards (CNS) specifications ( 210χ297 public shame) -68- — ^ —------........------ Order ------ (Please read the notes on the back before filling this page) A8 B8 C8 D8 6. The patent application scope number; and wherein the bidirectional device includes a piezoelectric converter for bending the audio input into a transmission signal and transforming the receiving signal representing audio data into an audio output. 56. — A full-duplex audio communication circuit that generates audio output and sends audio input at the same time. The circuit includes: a first piezoelectric converter for converting an audio input into an electrical transmission signal, and for converting The electrical reception signal representing audio data is audio output; and an audio processing circuit connected to the first converter for receiving a combined signal, including a transmission signal and a reception signal, for simultaneously expanding the transmission signal and compressing the reception signal, In order to generate an output transmission signal, the loop gain of the audio processing circuit is lower than one. (Please read the notes on the back before filling out this page) Printed by the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs This paper size applies to China National Standard (CNS) A4 (210X297 mm) _ 69-