A signal processing circuit and device based on DisEqc

Abstract

The present invention provides a signal processing circuit based on DisEqc, which is serially connected between a high-frequency head and a cable TV coaxial cable, and includes: a filtering module: used to receive satellite signals and filter data signals in satellite signals; a sampling module: connected to the filtering module, used to filter DC signals in satellite signals; a comparison module: coupled to the sampling module, used to convert the signal output by the sampling module into a digital signal; a shaping module: connected to the comparison module, used to shape the signal output by the comparison module; an expansion module: connected to the shaping module, used to expand the signal processed by the shaping module and output it. The signal processing circuit of the present invention can effectively remove interference signals, ensure the integrity of the DisEqc signal, and at the same time improve the anti-interference ability of the DisEqc signal.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite signal reception, and in particular to a signal processing circuit and device based on DisEqc. Background Art

[0002] A satellite receiver is a device that receives satellite TV signals. It mainly includes an indoor receiver, an outdoor LNB (high-frequency head) and an outdoor antenna. The indoor receiver is connected to the outdoor LNB through a TV Cable (cable TV coaxial cable), which supplies power to the LNB and controls the signal switching of the LNB. At the same time, the LNB transmits the received satellite signal to the indoor receiver through the TV Cable for decoding, thereby restoring the TV signal. The indoor receiver controls the outdoor LNB through the DisEqC signal. DisEqC is called digital satellite control. It has different standard versions such as 1.0, 1.1, 1.2, and 2.0. The DisEqC control signal is modulated at a frequency of 22KHz, and its amplitude is + / -0.5V.

[0003] There are currently the following issues:

[0004] 1. Since the satellite receiver is placed indoors and the LNB is placed outdoors, the TV Cable is required to provide DC power and data transmission. When the length of the TV Cable is greater than 100 meters, the outdoor LNB switches the signal, causing the power consumption to increase, so that the voltage amplitude of the 22K signal on the DC power supply changes, resulting in abnormal DisEqC signals received by the LNB;

[0005] 2. As LNB has more and more functions, its power consumption is increasing. When a satellite receiver is connected to multiple LNBs, the increased power consumption of LNB has a greater impact on the voltage amplitude of the 22K signal, which may also cause the LNB to receive the DisEqC signal abnormally.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The first object of the present invention is to provide a signal processing circuit based on DisEqc, which can effectively reduce interference signals, prevent voltage amplitude changes from affecting signals, and ensure the integrity of DisEqc signals by filtering and expanding signals received by LNB.

[0008] The second object of the present invention is to provide a signal processing device using the above-mentioned signal processing circuit, which has a simple structure, is easy to use, and can effectively improve the reception quality of the signal and ensure the integrity of the signal.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] The present invention provides a signal processing circuit based on DisEqc, which is connected in series between a high-frequency head and a coaxial cable of a cable television, and comprises:

[0011] Filter module: used to receive satellite signals and filter data signals in satellite signals;

[0012] Sampling module: connected to the filtering module, used to filter the DC signal in the satellite signal;

[0013] Comparison module: coupled to the sampling module, used to convert the signal output by the sampling module into a digital signal;

[0014] Shaping module: connected to the comparison module, used for shaping the signal output by the comparison module;

[0015] Amplification module: connected to the shaping module, used to expand the signal processed by the shaping module and output it.

[0016] In the prior art, an indoor receiver is generally directly connected to an outdoor LNB via a TV Cable. However, since the satellite receiver is placed indoors and the LNB is placed outdoors, a TV Cable is required to provide DC power and data transmission. When the length of the TV Cable is greater than 100 meters, the outdoor LNB signal switching causes the power consumption to increase, thereby changing the voltage amplitude of the 22K signal on the DC power supply, thereby causing the DisEqC signal received by the LNB to be abnormal. In addition, since the functions of the LNB are increasing, its power consumption is increasing. When a satellite receiver is connected to multiple LNBs, the increased power consumption of the LNB has a greater impact on the voltage amplitude of the 22K signal, which may also cause the LNB to receive an abnormal DisEqC signal.

[0017] In order to solve the above technical problems, the present invention separates the DisEqc signal through a filtering module and a sampling module, effectively preventing other signals from interfering with the DisEqc signal, and filters the interference signal through a shaping module to obtain a complete DisEqc signal. The signal amplitude is increased through an amplitude expansion circuit, thereby further improving the signal's anti-interference ability.

[0018] Preferably, the filtering module includes a magnetic bead, one end of which is coupled to a high-frequency head, and the other end is connected to the sampling module. The signal received by the LBN includes a 13 / 18V DC signal, a DisEqc signal, and a 170MHz-1800MHz satellite signal. By setting the magnetic bead, the 170M-1800MHz signal can be isolated, and the DC signal and the DisEqc signal can be output to the next level circuit.

[0019] Preferably, the sampling module includes two first capacitors, and the two first capacitors are connected in parallel. By setting two first capacitors, the DC signal can be filtered by utilizing the property of capacitors that they block DC and pass AC, and the DisEqc signal can be output to the next level circuit.

[0020] Preferably, the comparison module includes a comparison chip, a first resistor, a first power supply and a second capacitor; the first pin of the comparison chip is connected to the sampling module; one end of the first resistor is connected to the first pin of the comparison chip, and the other end is grounded; the second pin of the comparison chip is grounded; the fifth pin of the comparison chip is connected to the second power supply; one end of the second capacitor is connected to the second power supply, and the other end is grounded. Further, the comparison chip is a U1403 chip. The signal of DisEqc is converted into a 3.3V square wave digital signal by the comparison chip and output to the next level circuit; the second capacitor is set to filter the second power supply, short-circuit the AC signal to the ground terminal, and then give the DC signal to the comparison chip.

[0021] Preferably, the comparison module further includes a second resistor and a third resistor; one end of the second resistor is connected to the third pin of the comparison chip, and the other end is connected to the first power supply; one end of the third resistor is connected to the third pin of the comparison chip, and the other end is grounded. The second resistor and the third resistor form a voltage divider circuit, and the opening threshold of the comparison chip can be controlled by adjusting the voltage of the voltage divider circuit.

[0022] Preferably, the shaping module includes a first transistor, a fourth resistor and a fifth resistor; one end of the fourth resistor is connected to the base of the first transistor, and the other end is connected to the fourth pin of the comparison chip; one end of the fifth resistor is connected to the collector of the first transistor, and the other end is connected to a shaping power supply; the emitter of the first transistor is grounded. Since the comparison circuit converts the AC signal extracted from the TV cable into a square wave signal of DisEqc, it will also convert part of the interference signal into a square wave; the shaping circuit is set to enable the square wave signal of DisEqc and the interference pulse signal output by the comparison circuit to pass through the first transistor. Since the interference signal is only a very short interference pulse and the first transistor has a certain conduction delay, the interference pulse signal cannot turn on the first transistor, and only the square wave signal of DisEqc can turn on the first transistor, so that the interference pulse signal can be filtered out, thereby outputting a complete DisEqc signal.

[0023] Preferably, the expansion module includes a second triode, a sixth resistor and a seventh resistor, one end of the sixth resistor is connected to the base of the second triode, and the other end is connected to the collector of the first triode; one end of the seventh resistor is connected to the base of the second triode, and the other end is grounded; the emitter of the second triode is grounded. The sixth resistor and the seventh resistor form a voltage-dividing and current-limiting network to prevent the second triode from burning out due to excessive current.

[0024] Preferably, the expansion module further includes a first diode, a second diode, an eighth resistor and a field effect transistor; the first pin of the eighth resistor is connected to the collector of the second transistor, the second pin of the eighth resistor is connected to the second pin of the field effect transistor; the first pin of the field effect transistor is connected to the collector of the second transistor; the second pin of the field effect transistor is connected to the first pin of the first diode; the second pin of the first diode is connected to the first pin of the second diode, the second pin of the second diode is connected to the third pin of the field effect transistor; the third pin of the field effect transistor is coupled to the cable TV coaxial cable. Furthermore, the second pin of the eighth resistor is connected to a DC signal source. An amplitude expansion circuit is formed by the second triode, the field effect tube, the first diode and the second diode; when the field effect tube is turned on, the current of the DC signal source is output to the TV Cable through the field effect tube, and enters the indoor receiver through the TV Cable. At this time, the voltages at the two points are the same; when the field effect tube is turned off, the current of the DC signal source passes through the first diode and the second diode, and enters the indoor receiver through the TV Cable. At this time, the voltage at the DC signal source is 1.4V-2.5V higher than that of the indoor receiver; since the conduction and cutoff of the field effect tube are controlled by the DisEqc signal that has been sampled and shaped before, it can restore the DisEqc signal very well.

[0025] Preferably, the first diode is connected in parallel with a ninth resistor, and the second diode is connected in parallel with a tenth resistor. The parallel resistors can play a role in current shunting, thereby improving the safety of the circuit.

[0026] The present invention further provides a signal processing device, comprising a housing, wherein a PCB board is arranged in the housing, and the PCB board is provided with the above-mentioned signal processing circuit based on DisEqc.

[0027] The signal processing device of the present invention has a simple structure and is easy to use, and can effectively improve the anti-interference capability of the DisEqc signal and ensure the integrity of the signal.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention separates the DisEqc signal through a filtering module and a sampling module, effectively preventing other signals from interfering with the DisEqc signal;

[0030] (2) The interference signal is filtered through the shaping module to ensure the integrity of the DisEqc signal;

[0031] (3) The signal amplitude is increased through the amplitude expansion circuit, thereby further improving the signal's anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0033] Figure 1 A circuit diagram of a signal processing circuit provided by an embodiment of the present invention;

[0034] Figure 2 A circuit diagram of a filter module provided in an embodiment of the present invention;

[0035] Figure 3 A circuit diagram of a sampling module provided by an embodiment of the present invention;

[0036] Figure 4 A circuit diagram of a comparison module provided by an embodiment of the present invention;

[0037] Figure 5 A circuit diagram of a shaping module provided in an embodiment of the present invention;

[0038] Figure 6 A circuit diagram of an expansion module provided in an embodiment of the present invention. Description of the drawings:

[0040] 10-filtering module; 20-sampling module;

[0041] 30- comparison module; 40- shaping module;

[0042] 50-Expansion module. DETAILED DESCRIPTION

[0043] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0044] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In order to more clearly explain the technical solution of the present invention, it is described in the form of specific embodiments below.

[0047] Example

[0048] See also Figure 1-6 As shown, this embodiment provides a signal processing circuit based on DisEqc, which is connected in series between a high-frequency head and a cable TV coaxial cable, including:

[0049] Filter module 10: used for receiving satellite signals and filtering data signals in the satellite signals;

[0050] Sampling module 20: connected to the filtering module 10, used to filter the DC signal in the satellite signal;

[0051] Comparison module 30: coupled to sampling module 20, used to convert the signal output by sampling module 20 into a digital signal;

[0052] Shaping module 40: connected to comparison module 30, used for shaping the signal output by comparison module 30;

[0053] Amplification module 50: connected to shaping module 40, used for expanding the amplitude of the signal processed by shaping module 40 and outputting it.

[0054] Among them, Figure 2 As shown, the filter module 10 includes a magnetic bead L1432, one end of which is coupled to a high-frequency head, and the other end is connected to a sampling module 20. The signal received by the LBN (high-frequency head) includes a 13 / 18V DC signal, a DisEqc signal, and a 170MHz-1800MHz satellite signal. When working, the magnetic bead L1432 can isolate the 170M-1800MHz signal and output the DC signal and the DisEqc signal to the next level circuit. The magnetic bead used in this embodiment is the magnetic bead BLM18HE152SN1D of Murata.

[0055] like Figure 3 As shown, the sampling module 20 includes two first capacitors, and the two first capacitors C1410 and C1411 are connected in parallel. When working, the sampling module 20 receives the 22K_IN output by the filtering module 10, filters the DC signal therein, and outputs the DisEqc signal 22K_AC to the next level circuit.

[0056] like Figure 4 As shown, the comparison module 30 includes a comparison chip, a first resistor R1416, a first power supply and a second capacitor; the first pin of the comparison chip is connected to the sampling module 20; one end of the first resistor is connected to the first pin of the comparison chip, and the other end is grounded; the second pin of the comparison chip is grounded; the fifth pin of the comparison chip is connected to the second power supply 3.3VD; one end of the second capacitor C1414 is connected to the second power supply 3.3VD, and the other end is grounded. Further, the comparison chip is a U1403 chip. The comparison chip converts the signal of DisEqc into a 3.3V square wave digital signal 22K_TTL, and outputs it to the next level circuit. The comparison chip in this embodiment is SGM8741YN5G / TR of SGMC.

[0057] The comparison module 30 also includes a second resistor R1417 and a third resistor R1420; one end of the second resistor R1417 is connected to the third pin of the comparison chip, and the other end is connected to the first power supply Vref 3.0; one end of the third resistor R1420 is connected to the third pin of the comparison chip, and the other end is grounded. The second resistor R1417 and the third resistor R1420 form a voltage divider circuit, and the opening threshold of the comparison chip can be controlled by adjusting the voltage of the voltage divider circuit. In this embodiment, the opening threshold of the comparison chip is 40mV.

[0058] like Figure 5 As shown, the shaping module 40 includes a first transistor Q1401, a fourth resistor R1438 and a fifth resistor R1429; one end of the fourth resistor R1438 is connected to the base of the first transistor Q1401, and the other end is connected to the fourth pin of the comparison chip to receive the signal 22K_TTL processed by the comparison module 30; one end of the fifth resistor R1429 is connected to the collector of the first transistor Q1401, and the other end is connected to a 3.3V shaping power supply; the emitter of the first transistor Q1401 is grounded. Since the comparison circuit converts the AC signal extracted from the TV cable into a square wave signal of DisEqc, it will also convert part of the interference signal into a square wave; the shaping circuit can make the square wave signal of DisEqc and the interference pulse signal output by the comparison circuit pass through the first transistor Q1401. Since the interference signal is only a very short interference pulse and the first transistor Q1401 has a certain conduction delay, the interference pulse signal cannot turn on the first transistor Q1401. Only the square wave signal of DisEqc can turn on the first transistor Q1401, so that the interference pulse signal can be filtered out, thereby outputting a complete DisEqc signal. In this embodiment, Q1401 uses 2SC5585 of Changdian Company.

[0059] Among them, the high and low level time of the DisEqc signal can be adjusted by the switch delay of the first transistor Q1401. Specifically, when 22K_TTL is at a high level, the first transistor Q1401 is turned on, and 22K_TTL_R outputs a low level! When 22K_TTL is at a low level, the first transistor Q1401 is turned off and 22K_TTL_R outputs a high level. The base current of the first transistor Q1401 can be increased or decreased by changing the resistance value of the fifth resistor R1429. When the fifth resistor R1429 is larger, the base current of the first transistor Q1401 is smaller, so that the conduction time of the first transistor Q1401 is shorter, and the high level time it outputs is longer, and the low level time is shorter; the smaller the fifth resistor R1429 is, the larger the base current of the first transistor Q1401 is, so that the conduction time of the first transistor Q1401 is longer, so that the high level it outputs is shorter, and the low level time is longer.

[0060] like Figure 6 As shown, the expansion module 50 includes a second triode Q1415, a sixth resistor R1444 and a seventh resistor R1447, one end of the sixth resistor R1444 is connected to the base of the second triode Q1415, and the other end is connected to the collector of the first triode Q1401 to receive the signal 22K_TTL_R sent by the shaping module 40; one end of the seventh resistor R1447 is connected to the base of the second triode Q1415, and the other end is grounded; the emitter of the second triode Q1415 is grounded. The sixth resistor R1444 and the seventh resistor R1447 form a voltage-dividing and current-limiting network, which can prevent the second triode Q1415 from being burned out due to excessive current.

[0061] Among them, the expansion module 50 also includes a first diode D1404, a second diode D1405, an eighth resistor R1440 and a field effect transistor Q1410; the first pin of the eighth resistor R1440 is connected to the collector of the second transistor Q1415, and the second pin of the eighth resistor R1440 is connected to the second pin of the field effect transistor Q1410; the first pin of the field effect transistor Q1410 is connected to the collector of the second transistor Q1415; the second pin of the field effect transistor Q1410 is connected to the first pin of the first diode D1404; the second pin of the first diode D1404 is connected to the first pin of the second diode D1405, and the second pin of the second diode D1405 is connected to the third pin of the field effect transistor Q1410; the first diode D1404 is connected in parallel with a ninth resistor R1427, and the second diode D1405 is connected in parallel with a tenth resistor R1428; the third pin of the field effect transistor Q1410 is coupled to the cable TV coaxial cable. Furthermore, the second pin of the eighth resistor R1440 is connected to a DC signal source DC_POWER. An expansion circuit is formed by the second triode Q1415, the field effect tube Q1410, the first diode D1404 and the second diode D1405; when the field effect tube Q1410 is turned on, the current of the DC signal source DC_POWER passes through the field effect tube Q1410 to output the signal DC_POWEROUT to the TV Cable, and enters the indoor receiver through the TV Cable, at which time the voltages of the two points are the same; when the field effect tube Q1410 is turned off, the current of the DC signal source DC_POWER passes through the first diode D1404 and the second diode D1405, and enters the indoor receiver through TVCable, at which time the voltage at the DC signal source DC_POWER is 1.4V-2.5V higher than DC_POWEROUT; since the on and off of the field effect tube Q1410 is controlled by the previously sampled and shaped DisEqc signal, it can restore the DisEqc signal very well.

[0062] When in use, the signal processing circuit is connected in series to the TV Cable. At this time, after the signal is received by the LNB, the signal processing circuit processes the DisEqc signal, and the processed DisEqc signal enters the indoor receiver through the TV Cable.

[0063] In summary, the signal processing circuit of the present invention can effectively remove interference signals, ensure the integrity of the DisEqc signal, and improve the anti-interference ability of the DisEqc signal.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A signal processing circuit based on DisEqc, characterized in that: Connected in series between the high-frequency head and the cable TV coaxial cable, including: Filter module: used to receive satellite signals and filter data signals in satellite signals; Sampling module: connected to the filtering module, used to filter the DC signal in the satellite signal; Comparison module: coupled to the sampling module, used to convert the signal output by the sampling module into a digital signal; Shaping module: connected to the comparison module, used for shaping the signal output by the comparison module; Amplification module: connected to the shaping module, used to expand the signal processed by the shaping module and output it; The sampling module includes two first capacitors, and the two first capacitors are connected in parallel; The comparison module includes a comparison chip, a first resistor, a first power supply and a second capacitor; the first pin of the comparison chip is connected to the sampling module; one end of the first resistor is connected to the first pin of the comparison chip, and the other end is grounded; the second pin of the comparison chip is grounded; the fifth pin of the comparison chip is connected to the second power supply; one end of the second capacitor is connected to the second power supply, and the other end is grounded.

2. The signal processing circuit based on DisEqc according to claim 1, characterized in that: The filtering module comprises a magnetic bead, one end of which is coupled to a high-frequency head, and the other end of which is connected to the sampling module.

3. The signal processing circuit based on DisEqc according to claim 1, characterized in that: The comparison module also includes a second resistor and a third resistor; one end of the second resistor is connected to the third pin of the comparison chip, and the other end is connected to the first power supply; one end of the third resistor is connected to the third pin of the comparison chip, and the other end is grounded.

4. The signal processing circuit based on DisEqc according to claim 1, characterized in that: The shaping module includes a first transistor, a fourth resistor and a fifth resistor; one end of the fourth resistor is connected to the base of the first transistor, and the other end is connected to the fourth pin of the comparison chip; one end of the fifth resistor is connected to the collector of the first transistor, and the other end is connected to the shaping power supply; the emitter of the first transistor is grounded.

5. The DisEqc-based signal processing circuit according to claim 4, characterized in that: The expansion module includes a second triode, a sixth resistor and a seventh resistor, one end of the sixth resistor is connected to the base of the second triode, and the other end is connected to the collector of the first triode; one end of the seventh resistor is connected to the base of the second triode, and the other end is grounded; the emission electrode of the second triode is grounded.

6. The DisEqc-based signal processing circuit according to claim 5, characterized in that: The expansion module also includes a first diode, a second diode, an eighth resistor and a field effect transistor; the first pin of the eighth resistor is connected to the collector of the second transistor, and the second pin of the eighth resistor is connected to the second pin of the field effect transistor; the first pin of the field effect transistor is connected to the collector of the second transistor; the second pin of the field effect transistor is connected to the first pin of the first diode; the second pin of the first diode is connected to the first pin of the second diode, and the second pin of the second diode is connected to the third pin of the field effect transistor; the third pin of the field effect transistor is coupled to the cable TV coaxial cable.

7. The DisEqc-based signal processing circuit according to claim 6, characterized in that: A ninth resistor is connected in parallel with the first diode, and a tenth resistor is connected in parallel with the second diode.

8. A signal processing device, comprising a housing, wherein a PCB board is arranged in the housing, characterized in that: The PCB board is provided with a DisEqc-based signal processing circuit as described in any one of claims 1-7.

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