Communication device and digital to analog signal conversion circuit

Abstract

The present invention relates to a communication device and a digital-to-analog signal conversion circuit. The communication device comprises: a receiving end circuit and a transmitting end circuit comprising a signal processing circuit and a digital-to-analog signal conversion circuit. The digital-to-analog signal conversion circuit comprises: a main and a first hybrid conversion circuit. The main conversion circuit converts the transmission signal of the signal processing circuit for transmission from the signal transmission line. The first hybrid conversion circuit converts the transmission signal to the first receiving resistor to generate a voltage drop, so that the receiving end circuit receives a first actual receiving signal through the signal transmission line and the first receiving resistor. The main conversion circuit operates according to a first current including a first and a second part of the current, and the first hybrid conversion circuit operates according to the second current, and the first part of the current is not affected by the resistance change, and the second part of the current and the second current are affected by the resistance change.

Description

Technical Field

[0001] The present invention relates to circuit technology, and in particular to a communication device and a digital-to-analog signal conversion circuit thereof. Background Art

[0002] A common communication device includes a transmitting circuit and a receiving circuit. The transmitting circuit is used to convert the signal to be transmitted from a digital form to an analog form and then transmit it through a corresponding transmission channel. The receiving circuit is used to receive the signal from the corresponding transmission channel and convert it from an analog form to a digital form.

[0003] When both the transmitting circuit and the receiving circuit need to transmit and receive the transmitted signal and the received analog signal through resistors, these resistors are easily affected by environmental factors and change, further causing changes in the signal current. However, the equivalent impedance of the transmission channel relative to the transmitting circuit is not easily affected by environmental factors due to different materials. In the case where the characteristics of the resistors required for the operation of the entire communication device are different, how to maintain the signal level will become a difficult problem. Summary of the invention

[0004] In view of the problems of the prior art, an object of the present invention is to provide a communication device and a digital-to-analog signal conversion circuit thereof to improve the prior art.

[0005] The present invention includes a digital-to-analog signal conversion circuit, which is applied to a transmitting end circuit, and one embodiment thereof includes: a main conversion circuit and a first hybrid conversion circuit. The main conversion circuit is configured to receive a transmission signal from a signal processing circuit of the transmitting end circuit to perform a digital-to-analog signal conversion into an actual transmission signal, and transmit the actual transmission signal from a signal transmission line through a transmission resistor. The first hybrid conversion circuit is configured to receive a transmission signal from a signal processing circuit to perform a digital-to-analog signal conversion into a first reference transmission signal, and transmit the first reference transmission signal to a first receiving resistor between a receiving end circuit and a signal transmission line to generate a voltage drop, so that the receiving end circuit receives a first actual reception signal from the signal transmission line through the first receiving resistor through the voltage drop. The main conversion circuit operates according to a first current including a first part of the current and a second part of the current, and the first hybrid conversion circuit operates according to the second current, and the first part of the current is not affected by changes in the corresponding resistor, and the second part of the current and the second current are affected by changes in the corresponding resistor.

[0006] The present invention further includes a communication device, including: a receiving end circuit and a transmitting end circuit. The transmitting end circuit includes a signal processing circuit and a digital to analog signal conversion circuit. The signal processing circuit is configured to generate a transmission signal. The digital to analog signal conversion circuit includes: a main conversion circuit and a first hybrid conversion circuit. The main conversion circuit is configured to receive the transmission signal from the signal processing circuit, perform digital to analog signal conversion into an actual transmission signal, and transmit the actual transmission signal from the signal transmission line through a transmission resistor. The first hybrid conversion circuit is configured to receive the transmission signal from the signal processing circuit, perform digital to analog signal conversion into a first reference transmission signal, and transmit the first reference transmission signal to a first receiving resistor between the receiving end circuit and the signal transmission line to generate a voltage drop, so that the receiving end circuit receives the first actual reception signal from the signal transmission line through the first receiving resistor through the voltage drop. The main conversion circuit operates according to a first current including a first part of the current and a second part of the current, and the first hybrid conversion circuit operates according to the second current, and the first part of the current is not affected by the change of the corresponding resistor, and the second part of the current and the second current are affected by the change of the corresponding resistor.

[0007] The features, implementation and effects of the present invention are described in detail below with reference to the drawings as preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] [ Figure 1 ] shows a block diagram of a communication device in one embodiment of the present invention;

[0009] [ Figure 2 ] shows an embodiment of the present invention, Figure 1 A simplified circuit diagram of a digital to analog signal conversion circuit and a transmitting resistor, a first receiving resistor and a second receiving resistor. DETAILED DESCRIPTION

[0010] An object of the present invention is to provide a communication device and a digital-to-analog signal conversion circuit thereof, which supplies currents of different properties to the digital-to-analog signal conversion circuit according to resistance characteristics, so that the signal transmission level of the transmitting circuit and the receiving circuit is not affected by the corresponding resistance and can be maintained.

[0011] Please refer to Figure 1 . Figure 1 FIG. 1 is a block diagram of a communication device 100 according to an embodiment of the present invention. The communication device 100 comprises: a transmitting end circuit 110 ( Figure 1 TX in the figure) and the receiving end circuit 120 (in Figure 1 RX in the figure).

[0012] The transmitting end circuit 110 includes a signal processing circuit 130 and a digital-to-analog signal conversion circuit 135 .

[0013] In one embodiment, the digital-to-analog signal conversion circuit 135 is a part of the transmitting circuit 110. In this embodiment, the digital-to-analog signal conversion circuit 135 includes a main conversion circuit 140, a first hybrid conversion circuit 150 and a second hybrid conversion circuit 160.

[0014] The signal processing circuit 130 is configured to generate a transmission signal DTS in a digital form, and performs a digital-to-analog signal conversion via a main conversion circuit 140 electrically coupled to the signal processing circuit 130 to generate an actual transmission signal ATS in an analog form. In one embodiment, the main conversion circuit 140 includes a first transmission terminal T1 and a second transmission terminal T2, and outputs the actual transmission signal ATS in a differential manner.

[0015] In one embodiment, the first transmission terminal T1 and the second transmission terminal T2 of the main conversion circuit 140 are electrically coupled to the two sides of a transmission resistor RT, so as to output the actual transmission signal ATS to the transmission resistor RT through the first transmission terminal T1 and the second transmission terminal T2, so as to further transmit the actual transmission signal ATS to the transmission resistor RT through the transmission resistor RT, and then transmit the actual transmission signal ATS to the signal transmission line STW through the transmission resistor RT, and then transmit the actual transmission signal ATS to the external network module (not shown) through the signal transmission line STW. Figure 1 , an equivalent impedance RWI viewed from the main conversion circuit 140 is shown.

[0016] In one embodiment, the transmission resistor RT and the signal transmission line STW may selectively include a low pass filter LPF to filter the transmitted actual transmission signal ATS.

[0017] The receiving end circuit 120 includes a first receiving end R1 and a second receiving end R2. The first receiving end R1 is electrically coupled to the first transmitting end T1 through the first receiving resistor Rh1, and further electrically coupled to the signal transmission line STW through the first transmitting end T1. Similarly, the second receiving end R2 is electrically coupled to the second transmitting end T2 through the second receiving resistor Rh2, and further electrically coupled to the signal transmission line STW through the second transmitting end T2.

[0018] Through the above-mentioned path, the receiving end circuit 120 is configured to receive the analog receiving signal ARS from the same signal transmission line STW in a differential manner. In addition, the receiving end circuit 120 can convert the receiving signal ARS into a digital form by, for example, an analog to digital signal conversion circuit (not shown) provided therein. In one embodiment, since the receiving signal ARS is received in a differential manner, it actually includes a first actual receiving signal ARS1 received by the first receiving end R1 and a second actual receiving signal ARS2 received by the second receiving end R2.

[0019] However, since both the transmitting circuit 110 and the receiving circuit 120 transmit and receive signals through the signal transmission line STW, the receiving circuit 120 needs to deduct the actual transmission signal ATS from all the transmitted signals on the signal transmission line STW to obtain the real receiving signal ARS.

[0020] Therefore, corresponding to the first receiving resistor Rh1, the first hybrid conversion circuit 150 is configured to receive the transmission signal DTS from the signal processing circuit 130, perform digital-to-analog signal conversion into the first reference transmission signal RATS1, and transmit the first reference transmission signal RATS1 to the first receiving resistor Rh1 to generate a voltage drop, so that the receiving end circuit 120 receives the first actual receiving signal ARS1 from the signal transmission line STW through the first receiving resistor Rh1 after the voltage drop.

[0021] Correspondingly, corresponding to the second receiving resistor Rh2, the second hybrid conversion circuit 160 is configured to receive the transmission signal DTS from the signal processing circuit 130, perform digital-to-analog signal conversion into a second reference transmission signal RATS2, and transmit the second reference transmission signal RATS2 to the second receiving resistor Rh2 to generate a voltage drop, so that the receiving end circuit 120 receives the second actual receiving signal ARS2 from the signal transmission line STW through the second receiving resistor Rh2 after the voltage drop.

[0022] In order to balance the first actual receiving signal ARS1 and the second actual receiving signal ARS2 , the voltage drop generated by the first receiving resistor Rh1 according to the first reference transmitting signal RATS1 and the voltage drop generated by the second receiving resistor Rh2 according to the second reference transmitting signal RATS2 are the same.

[0023] Furthermore, in order to ensure that the component of the actual transmission signal ATS deducted from all signals transmitted on the signal transmission line STW is indeed equivalent to the size of the actual transmission signal ATS, the voltage drop caused by the actual transmission signal ATS through the transmission resistor RT is equal to the voltage drop caused by the above-mentioned first reference transmission signal RATS1 through the first receiving resistor Rh1 and the second reference transmission signal RATS2 through the second receiving resistor Rh2.

[0024] In one embodiment, in order to achieve power saving, the resistance of the first receiving resistor Rh1 and the second receiving resistor Rh2 is greater than the resistance of the transmitting resistor RT, so that the first hybrid conversion circuit 150 and the second hybrid conversion circuit 160 can generate the first reference transmitting signal RATS1 and the second reference transmitting signal RATS2 with smaller current to achieve the same voltage drop.

[0025] Please refer to Figure 2 . Figure 2In one embodiment of the present invention, Figure 1 FIG. 1 is a simplified circuit diagram of the digital-to-analog signal conversion circuit 135 and the transmitting resistor RT, the first receiving resistor Rh1 and the second receiving resistor Rh2.

[0026] It should be noted that in Figure 2 , only the connection relationship between the digital-to-analog signal conversion circuit 135 and the transmission resistor RT, the first receiving resistor Rh1 and the second receiving resistor Rh2 is illustrated, while the connection relationship between the digital-to-analog signal conversion circuit 135 and the signal processing circuit 130 and the receiving end circuit 120 is not illustrated.

[0027] like Figure 2 As shown, the main conversion circuit 140 in the digital-to-analog signal conversion circuit 135 operates according to the first current I1, and extends to the first transmission terminal T1 and the second transmission terminal T2 through the paths P1 and P2, and is electrically coupled to the transmission resistor RT. The first current I1 actually includes a first part current IP1 and a second part current IP2.

[0028] The first hybrid conversion circuit 150 operates according to the second current I2 and extends to the first receiving terminal R1 and the first transmitting terminal T1 through paths P3 and P4. The second hybrid conversion circuit 160 operates according to the third current I3 and extends to the second transmitting terminal T2 and the second receiving terminal R2 through paths P5 and P6.

[0029] Among the above currents, the first current IP1 is not affected by the change of the corresponding resistor, while the second current IP2, the second current I2 and the third current I3 are affected by the change of the corresponding resistor.

[0030] In more detail, the first part of the current IP1 is a constant current. When the main conversion circuit 140 operates according to the first current I1 to generate the actual transmission signal ATS, a part of the current of the actual transmission signal ATS will not change with any change of resistance due to the existence of the first part of the current IP1.

[0031] When the main conversion circuit 140 generates the actual transmission signal ATS according to the first current I1, another part of the current of the actual transmission signal ATS changes due to the change of the second current IP2 with the change of the transmission resistor RT.

[0032] In contrast, when the first hybrid conversion circuit 150 and the second hybrid conversion circuit 160 respectively operate according to the second current I2 and the third current I3 to generate the first actual receiving signal ARS1 and the second actual receiving signal ARS2, the currents of the first actual receiving signal ARS1 and the second actual receiving signal ARS2 will change with the changes of the first receiving resistor Rh1 and the second receiving resistor Rh2 due to the second current I2 and the third current I3.

[0033] In one embodiment, in order to maintain the same signal level, when the resistance values ​​of the resistors (e.g., the transmitting resistor RT, the first receiving resistor Rh1, and the second receiving resistor Rh2) corresponding to each variable current, such as the second partial current IP2, the second current I2, and the third current I3, increase due to temperature or other environmental factors, the second partial current IP2, the second current I2, and the third current I3 will decrease. When the resistance values ​​of the resistors corresponding to the second partial current IP2, the second current I2, and the third current I3 decrease due to temperature or other environmental factors, the second partial current IP2, the second current I2, and the third current I3 will increase.

[0034] When the communication device 100 is in operation, the transmission resistor RT, the first receiving resistor Rh1, and the second receiving resistor Rh2 will be affected by temperature or other environmental factors and change their resistance values. In order to compensate for such effects, the first current I1, the second current I2, and the third current I3 used to drive the digital-to-analog signal conversion circuit 135 to operate need to change accordingly. However, for the main conversion circuit 140 that is directly electrically coupled to the signal transmission line STW through the transmission resistor RT, it will be affected by the equivalent impedance RWI of the signal transmission line STW.

[0035] The transmission resistor RT, the first receiving resistor Rh1 and the second receiving resistor Rh2 are usually formed by the same process and have the same material. However, the signal transmission line STW and these resistors are made of different materials, and their equivalent impedance RWI is almost unchanged. If all the current components of the first current I1 change with the transmission resistor RT, when the equivalent impedance RWI remains unchanged, the level of the actual transmission signal ATS will change.

[0036] Therefore, the digital-to-analog signal conversion circuit 135 of the communication device 100 of the present invention can be used to drive the first current I1 of the main conversion circuit 140, which includes a first part of the current IP1 that does not change with the change of any resistance and a second part of the current IP2 that changes with the change of the corresponding resistance. It can adapt to the change of part of the current due to environmental factors in the internal resistance, and can also maintain part of the current in response to the unchanged equivalent impedance RWI, while avoiding the influence of the internal resistance and the equivalent impedance of the signal transmission line.

[0037] In one embodiment, the first portion of current IP1 and the second portion of current IP2 are equal in value, so as to balance the influence of the internal resistance and the equivalent impedance of the signal transmission line.

[0038] It should be noted that the above implementation is only an example. In other embodiments, those skilled in the art may make changes without violating the spirit of the present invention.

[0039] In summary, the digital to analog signal conversion circuit of the communication device of the present invention can simultaneously adapt to the influence of environmental factors on the internal resistance and the influence of the unchanged equivalent impedance of the signal transmission line, so that the signal transmission level between the transmitting circuit and the receiving circuit can be maintained.

[0040] Although the embodiments of the present invention are described above, these embodiments are not intended to limit the present invention. Those with ordinary knowledge in the technical field may make changes to the technical features of the present invention based on the explicit or implicit contents of the present invention. All these changes may fall within the scope of patent protection sought by the present invention. In other words, the scope of patent protection of the present invention shall be subject to the scope of the patent application defined in this specification.

[0041]

Explanation of symbols

[0042] 100 communication devices

[0043] 110 Transmitter circuit

[0044] 120 Receiver Circuit

[0045] 130 signal processing circuit

[0046] 135 Digital to analog signal conversion circuit

[0047] 140 Main conversion circuit

[0048] 150 First hybrid conversion circuit

[0049] 160 Second hybrid conversion circuit

[0050] ARS receiving signal

[0051] ARS1 First actual received signal

[0052] ARS2 Second actual received signal

[0053] ATS actually transmits the signal

[0054] DTS Transmit Signal

[0055] LPF Low Pass Filter

[0056] I1 First current

[0057] I2 Second current

[0058] I3 Third current

[0059] IP1 First part current

[0060] IP2 Second part current

[0061] P1~P6 Path

[0062] R1 First receiving end

[0063] R2 Second receiving end

[0064] RATS1 First reference transmit signal

[0065] RATS2 Second reference transmit signal

[0066] Rh1 First receiving resistor

[0067] Rh2 Second receiving resistor

[0068] RT Transfer resistance

[0069] RWI equivalent impedance

[0070] STW signal transmission line

[0071] T1 First Transmission Terminal

[0072] T2 Second transmission terminal.

Claims

1. A digital to analog signal conversion circuit, applied to a transmitting end circuit, comprising: a main conversion circuit configured to receive a transmission signal from a signal processing circuit of the transmission end circuit, perform digital-to-analog signal conversion into an actual transmission signal, and transmit the actual transmission signal from a signal transmission line through a transmission resistor; and a first hybrid conversion circuit, configured to receive the transmission signal from the signal processing circuit, perform digital-to-analog signal conversion into a first reference transmission signal, and transmit the first reference transmission signal to a first receiving resistor between a receiving end circuit and the signal transmission line, wherein the current of the first reference transmission signal passes through the first receiving resistor to generate a voltage drop, so that the receiving end circuit receives a first actual reception signal from the signal transmission line through the first receiving resistor and through the voltage drop, wherein the first actual reception signal is obtained by passing the first reference transmission signal through the voltage drop; in, The main conversion circuit converts the transmission signal from digital to analog signal into the actual transmission signal according to a first current including a first part of the current and a second part of the current, the first part of the current is a constant current, and the second part of the current is a variable current. The first hybrid conversion circuit also receives a second current to generate the first actual reception signal, the second current is a variable current, the second part of the current changes with the change of the transmission resistance, and the second current changes with the change of the first receiving resistance.

2. The digital to analog signal conversion circuit according to claim 1, wherein the main conversion circuit comprises a first transmission end and a second transmission end, electrically coupled to both sides of the transmission resistor, so as to output the actual transmission signal to the transmission resistor through the first transmission end and the second transmission end, so as to be further transmitted to the signal transmission line through the transmission resistor. 3 . The digital-to-analog signal conversion circuit according to claim 2 , wherein the first receiving resistor is electrically coupled to a first receiving end of the receiving end circuit, and is electrically coupled to the signal transmission line through the first transmitting end.

4. The digital-to-analog signal conversion circuit according to claim 3, further comprising: a second hybrid conversion circuit, configured to receive the transmission signal from the signal processing circuit, perform digital-to-analog signal conversion into a second reference transmission signal, and transmit the second reference transmission signal to a second receiving resistor between the receiving end circuit and the signal transmission line, the current of the second reference transmission signal passes through the second receiving resistor to generate the voltage drop, so that the receiving end circuit receives a second actual reception signal from the signal transmission line through the second receiving resistor through the voltage drop, and the second actual reception signal is obtained by the second reference transmission signal through the voltage drop; The second receiving resistor is electrically coupled to a second receiving end of the receiving end circuit and is electrically coupled to the signal transmission line through the second transmitting end. The second hybrid conversion circuit generates the second actual receiving signal according to a third current operation. The third current is a variable current and changes with the change of the second receiving resistor.

5. The digital to analog signal conversion circuit according to claim 1, wherein when the second portion of the current and the resistance corresponding to the second current increase, the current of the second portion of the current and the second current decreases, and when the second portion of the current and the resistance corresponding to the second current decreases, the current of the second portion of the current and the second current increases. 6 . The digital-to-analog signal conversion circuit according to claim 1 , wherein the transmitting resistor is made of the same material as the first receiving resistor and is made of a different material from the signal transmission line. 7 . The digital-to-analog signal conversion circuit as claimed in claim 1 , wherein the first portion of current and the second portion of current are equal in value.

8. The digital to analog signal conversion circuit according to claim 1, wherein: The resistance values ​​of the first receiving resistor and the second receiving resistor are greater than the resistance value of the transmitting resistor, so that the first hybrid conversion circuit and the second hybrid conversion circuit generate the first reference transmitting signal and the second reference transmitting signal having a current smaller than the current of the actual transmitting signal, and the voltage drop caused by the first current causing the actual transmitting signal to pass through the transmitting resistor is equal to the voltage drop caused by the second current causing the first reference transmitting signal to pass through the first receiving resistor. 9 . The digital-to-analog signal conversion circuit as claimed in claim 8 , wherein a resistance value of the first receiving resistor is greater than a resistance value of the transmitting resistor.

10. A communication device, comprising: a receiving circuit; and A transmitting circuit comprising a signal processing circuit configured to generate a transmission signal; and A digital to analog signal conversion circuit comprising: a main conversion circuit configured to receive the transmission signal from the signal processing circuit, perform digital-to-analog signal conversion into an actual transmission signal, and transmit the actual transmission signal from a signal transmission line through a transmission resistor; and a first hybrid conversion circuit, configured to receive the transmission signal from the signal processing circuit, perform digital-to-analog signal conversion into a first reference transmission signal, and transmit the first reference transmission signal to a first receiving resistor between a receiving end circuit and the signal transmission line, wherein the current of the first reference transmission signal passes through the first receiving resistor to generate a voltage drop, so that the receiving end circuit receives a first actual reception signal from the signal transmission line through the first receiving resistor and through the voltage drop, wherein the first actual reception signal is obtained by passing the first reference transmission signal through the voltage drop; in, The main conversion circuit converts the transmission signal from digital to analog signal into the actual transmission signal according to a first current including a first part of the current and a second part of the current, the first part of the current is a constant current, and the second part of the current is a variable current. The first hybrid conversion circuit also receives a second current to generate the first actual reception signal, the second current is a variable current, the second part of the current changes with the change of the transmission resistance, and the second current changes with the change of the first receiving resistance.

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