CN203015053U - Set-top box digital voice-frequency circuit - Google Patents
Set-top box digital voice-frequency circuit Download PDFInfo
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- CN203015053U CN203015053U CN 201220651605 CN201220651605U CN203015053U CN 203015053 U CN203015053 U CN 203015053U CN 201220651605 CN201220651605 CN 201220651605 CN 201220651605 U CN201220651605 U CN 201220651605U CN 203015053 U CN203015053 U CN 203015053U
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Abstract
The utility model discloses a set-top box digital voice-frequency circuit. The set-top box digital voice-frequency circuit is connected with an IO interface of a processor. The set-top box digital voice-frequency circuit includes an emitter-following circuit and a filtering circuit; an input end of the emitter-following circuit is connected with the IO interface; an output end of the emitter-following circuit is connected with an input end of the filtering circuit; and an output end of the filtering circuit is externally connected with a power amplification device. A first resistor can improve driving capability, and prevent the insufficiency of the driving capability of the IO interface of the processor such as a CPU; in addition, the emitter-following circuit is used for signal isolation and level conversion; signals outputted by the emitter-following circuit further pass the filtering circuit; after passing the filtering circuit, the signals are finally connected to the externally-connected power amplification device; and a high-frequency filtering capacitor can filter some high frequency harmonic signals, and prevent the radiation of the circuit from exceeding a standard.
Description
Technical field
The utility model relates to a kind of circuit arrangement field, relates in particular to a kind of set-top box digital audio circuit.
Background technology
The analogue audio frequency output tonequality of general set-top box does not have special power amplifying device good, and therefore increasing the application only requires that the set-top box output digit signals get final product, and the tonequality aspect is by the equipment assurance of rear class.SPDIF digital audio circuit is because anti-interference is better than common analog audio circuit, and therefore the utilization in the KTV set-top box is more and more extensive.The power amplifying device of specialty is mixed in SPDIF digital audio output, and it is very good that the tonequality aspect can be accomplished, this just depends on the audio frequency apparatus that rear class is used.There is shortcomings in existing SPDIF circuit, comprising:
1, signal amplitude is inadequate; 2, lack signal isolation and the double level conversion relevant treatment of doing; 3, radiation exceeds standard.
In addition, in the prior art, the IO of increasing CPU belongs to the system power supply of 3.3V, if the IO of CPU belongs to the 5V power supply, need not to do level shifting circuit, but will note improving the driving force of circuit, because the IO driving force of general CPU is all more weak, prevent that output level is not high enough; Directly from the output of CPU end, again this signal is received an another equipment, therefore due to digital signal, such interface will be carried out enough protection, prevents that the static surging signal from breaking CPU, therefore need to do signal isolation circuit, if system is 3.3V, also to doublely do level shifting circuit; Because the frequency ratio of SPDIF digital audio circuit is higher, therefore often can encounter the problem that radiation exceeds standard, can't by the relevant authentication requirement, therefore to note doing the measure that radiation proof exceeds standard.
The utility model content
The purpose of this utility model is to provide a kind of driving force good, can be good at protecting interface, and can doublely do level conversion, the circuit that shielding property is good.
In order to solve the problems of the technologies described above, the utility model provides a kind of set-top box digital audio circuit, is connected in the IO interface of processor, comprises and penetrating with circuit and filter circuit; Described penetrating with circuit, filter circuit includes input and output, and the described input of penetrating with circuit connects described IO interface, penetrates the input that connects described filter circuit with the output of circuit, the external power amplifying device of the output of filter circuit; Described penetrating with circuit comprises triode, the second resistance and biasing resistor, one end of described the second resistance is the input of penetrating with circuit, the other end connects the base stage of described triode, the grounded collector of described triode, emitter connects an end of described biasing resistor, another termination one power supply of described biasing resistor; Described filter circuit comprises current limliting unit, AC coupled unit and a high-frequency filter capacitor, described current limliting unit, AC coupled unit and High frequency filter unit include input and output, the input of described current limliting unit connects the emitter of described triode, the output of current limliting unit connects the input of described AC coupled unit, the output of AC coupled unit connects an end of described high-frequency filter capacitor, the other end ground connection of described high-frequency filter capacitor; The external power amplifying device in common node place of described AC coupled unit and described high-frequency filter capacitor.
Wherein, also comprise drive circuit, described drive circuit comprises one first resistance, and described the first resistance is a pull-up resistor; Described pull-up resistor one end connects the IO interface, and the other end is connected to power supply.
Wherein, described set-top box digital audio circuit also comprises a two-way voltage-stabiliser tube, and described voltage-stabiliser tube is in parallel with described high-frequency filter capacitor.
Wherein, described biasing resistor comprises the 3rd resistance and the 4th resistance, the emitter of described the 3rd resistance and an end connecting triode after the 4th resistance is in parallel, another termination one power supply.
Wherein, described AC coupled unit comprises the second electric capacity and the 4th electric capacity, and described the second electric capacity is connected mutually with the 4th electric capacity; One end of the second electric capacity connects the output of current limliting unit, and an end of the 4th electric capacity connects an end of described high-frequency filter capacitor; Also comprise the 3rd electric capacity and the 6th resistance; Described the 3rd electric capacity and the 6th resistance are parallel with one another, and rear one end in parallel connects the second electric capacity and the interconnective Nodes of the 4th electric capacity, other end ground connection.
Wherein, described current limliting unit comprises one the 5th resistance, the emitter of an end connection triode of described the 5th resistance, an end of described the second electric capacity of other end connection.
Further, described triode is the PNP pipe.
the beneficial effects of the utility model are: described set-top box digital audio circuit is connected in the signal output of the processor of set-top box, described the first resistance can improve driving force, prevent the driving force deficiency of the IO mouth of processor such as CPU etc., described penetrating with circuit in addition, be used for doing the double level conversion of signal isolation, through penetrating with the signal of circuit output wave circuit after filtration again, the concrete current-limiting circuit that comprises, ac-coupled circuit and a high-frequency filter capacitor, signal after wave circuit is connected on external power amplifying device at last after filtration, described high-frequency filter capacitor can some high-frequency harmonic signals of filtering, prevent that channel radiation from exceeding standard.
Description of drawings
Figure 1 shows that the structural representation of set-top box digital audio circuit of the present utility model.
1-penetrates the filter circuit with circuit 2-
Embodiment
By describing technology contents of the present utility model, structural feature in detail, being realized purpose and effect, below in conjunction with execution mode and coordinate accompanying drawing to be explained in detail.
A kind of set-top box digital audio circuit is connected in the IO interface of processor, comprises and penetrating with circuit and filter circuit;
In order to increase the driving force of described IO interface, in one embodiment, described set-top box digital audio circuit also comprises one drive circuit, and described drive circuit comprises one first resistance R 1, and described the first resistance R 1 is a pull-up resistor; Described pull-up resistor one end connects the IO interface; The other end is connected to the power supply place of 3.3V.In execution mode, described the first resistance R 1 is used for improving driving force, prevents that the IO driving force of CPU is not enough.
Described penetrating with circuit 1, filter circuit 2 includes input and output, and the described input of penetrating with circuit 1 connects described IO interface, penetrates the input that connects described filter circuit 2 with the output of circuit 1, the external power amplifying device of the output of filter circuit; As described in Figure 1, described power amplifying device is connected in the JP1 place.
Described penetrating with circuit 1 comprises triode Q1, the second resistance R 2 and biasing resistor, further, described triode is the PNP pipe, one end of described the second resistance R 2 is the input of penetrating with circuit, and the other end connects the base stage of described triode Q1, the grounded collector of described triode Q1, emitter connects an end of described biasing resistor, another termination one power supply of described biasing resistor, concrete, described power supply is the 5V power supply.Described biasing resistor comprises the 3rd resistance R 3 and the 4th resistance R 4, the emitter of an end connecting triode Q1 after described the 3rd resistance R 3 is in parallel with the 4th resistance R 4, another termination one power supply.Described the 3rd resistance R 3 is in parallel with the 4th resistance R 4 and be connected the other end ground connection of one first capacitor C 1, the first capacitor C 1 with the end that power supply joins.Described the first capacitor C 1 is used for the decoupling of 5V-VCC power supply.Wherein triode Q1 and the 3rd resistance R 3, the 4th resistance R 4 and described 5V power supply composition are penetrated with circuit, are used for doing the double level conversion of signal isolation.Directly protection CPU, prevent that the CPU pin from directly exporting, and penetrates in addition with circuit band level shifting circuit, and general SPDIF digital audio circuit is the system of 5V, therefore level need to be brought up to 5V.
Described filter circuit comprises current limliting unit, AC coupled unit and a high-frequency filter capacitor, described current limliting unit, AC coupled unit and High frequency filter unit include input and output, the input of described current limliting unit connects the emitter of described triode, the output of current limliting unit connects the input of described AC coupled unit, the output of AC coupled unit connects an end of described high-frequency filter capacitor, the other end ground connection of described high-frequency filter capacitor; The external power amplifying device in common node place of described AC coupled unit and described high-frequency filter capacitor.Described AC coupled unit can be according to the needs design capacitance of practical application, and in the technical program, described AC coupled unit comprises the second capacitor C 2 and the 4th capacitor C 4, and described the second capacitor C 2 is connected mutually with the 4th capacitor C 4; One end of the second capacitor C 2 connects the output of current limliting unit, and an end of the 4th capacitor C 4 connects the end of described high-frequency filter capacitor C5; Also comprise the 3rd capacitor C 3 and the 6th resistance R 6; Described the 3rd capacitor C 3 and the 6th resistance R 6 are parallel with one another, and rear one end in parallel connects the second capacitor C 2 and the 4th interconnective Nodes of capacitor C 4, other end ground connection.Described the 3rd capacitor C 3 is used for filtering, and the 6th resistance R 6 is used for drop-down.
Described high-frequency filter capacitor C5 plays an important role in the technical program, it is mainly used in some high-frequency harmonic signals of interface end filtering, prevent that channel radiation from exceeding standard, the resistance of high-frequency filter capacitor C5 is selected very important, too large can affect signal quality, and then affect tonequality, too little can not play obvious effect, in the technical program, the value of described high-frequency filter capacitor is preferably between 100p-1000p.
Described current limliting unit comprises one the 5th resistance R 5, and an end of described the 5th resistance R 5 connects the emitter of triode Q1, and the other end connects an end of described the second capacitor C 2.The 5th resistance R 5 is used for current limliting.
Described set-top box digital audio circuit also comprises a two-way voltage-stabiliser tube D1, and described voltage-stabiliser tube is in parallel with described high-frequency filter capacitor C5.Described bi-directional voltage stabilizing pipe D1 is the interface protective device, is used for protection static and surge.
The above is only embodiment of the present utility model; not thereby limit the scope of the claims of the present utility model; every equivalent structure or equivalent flow process conversion that utilizes the utility model specification and accompanying drawing content to do; or directly or indirectly be used in other relevant technical fields, all in like manner be included in scope of patent protection of the present utility model.
Claims (8)
1. set-top box digital audio circuit is connected in the IO interface of processor, it is characterized in that: comprise and penetrating with circuit and filter circuit;
Described penetrating with circuit, filter circuit includes input and output, and the described input of penetrating with circuit connects described IO interface, penetrates the input that connects described filter circuit with the output of circuit, the external power amplifying device of the output of filter circuit;
Described penetrating with circuit comprises triode, the second resistance and biasing resistor, one end of described the second resistance is the input of penetrating with circuit, the other end connects the base stage of described triode, the grounded collector of described triode, emitter connects an end of described biasing resistor, another termination one power supply of described biasing resistor;
Described filter circuit comprises current limliting unit, AC coupled unit and a high-frequency filter capacitor, described current limliting unit, AC coupled unit and High frequency filter unit include input and output, the input of described current limliting unit connects the emitter of described triode, the output of current limliting unit connects the input of described AC coupled unit, the output of AC coupled unit connects an end of described high-frequency filter capacitor, the other end ground connection of described high-frequency filter capacitor; The external power amplifying device in common node place of described AC coupled unit and described high-frequency filter capacitor.
2. set-top box digital audio circuit according to claim 1, it is characterized in that: also comprise one drive circuit, described drive circuit comprises one first resistance, and described the first resistance is a pull-up resistor; Described pull-up resistor one end connects the IO interface, and the other end is connected to power supply.
3. set-top box digital audio circuit according to claim 2, it is characterized in that: also comprise a two-way voltage-stabiliser tube, described bi-directional voltage stabilizing pipe is in parallel with described high-frequency filter capacitor.
4. set-top box digital audio circuit according to claim 1 and 2, it is characterized in that: described biasing resistor comprises the 3rd resistance and the 4th resistance, the emitter of described the 3rd resistance and an end connecting triode after the 4th resistance is in parallel, another termination one power supply.
5. set-top box digital audio circuit according to claim 4 is characterized in that: described the 3rd resistance is in parallel with the 4th resistance and be connected one first electric capacity, the other end ground connection of the first electric capacity with a end that power supply joins.
6. set-top box digital audio circuit according to claim 1 and 2 is characterized in that: described AC coupled unit comprises the second electric capacity and the 4th electric capacity, and described the second electric capacity is connected mutually with the 4th electric capacity; One end of the second electric capacity connects the output of current limliting unit, and an end of the 4th electric capacity connects an end of described high-frequency filter capacitor;
Also comprise the 3rd electric capacity and the 6th resistance; Described the 3rd electric capacity and the 6th resistance are parallel with one another, and rear one end in parallel connects the second electric capacity and the interconnective Nodes of the 4th electric capacity, other end ground connection.
7. set-top box digital audio circuit according to claim 1 and 2 is characterized in that: described current limliting unit comprises one the 5th resistance, and an end of described the 5th resistance connects the emitter of triode, and the other end connects an end of described the second electric capacity.
8. set-top box digital audio circuit according to claim 1 and 2 is characterized in that: described triode is the PNP pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220651605 CN203015053U (en) | 2012-11-30 | 2012-11-30 | Set-top box digital voice-frequency circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220651605 CN203015053U (en) | 2012-11-30 | 2012-11-30 | Set-top box digital voice-frequency circuit |
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| Publication Number | Publication Date |
|---|---|
| CN203015053U true CN203015053U (en) | 2013-06-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220651605 Expired - Lifetime CN203015053U (en) | 2012-11-30 | 2012-11-30 | Set-top box digital voice-frequency circuit |
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| CN (1) | CN203015053U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103888760A (en) * | 2014-03-19 | 2014-06-25 | 深圳市九洲电器有限公司 | Set top box radiation and video quality debugging method and device |
-
2012
- 2012-11-30 CN CN 201220651605 patent/CN203015053U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103888760A (en) * | 2014-03-19 | 2014-06-25 | 深圳市九洲电器有限公司 | Set top box radiation and video quality debugging method and device |
| CN103888760B (en) * | 2014-03-19 | 2016-01-20 | 深圳市九洲电器有限公司 | A kind of Set Top Box radiation and video quality adjustment method and device |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130619 |
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| CX01 | Expiry of patent term |