CN105391959B - Signal synthesis circuit - Google Patents
Signal synthesis circuit Download PDFInfo
- Publication number
- CN105391959B CN105391959B CN201410456447.XA CN201410456447A CN105391959B CN 105391959 B CN105391959 B CN 105391959B CN 201410456447 A CN201410456447 A CN 201410456447A CN 105391959 B CN105391959 B CN 105391959B
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- Prior art keywords
- signal
- capacitor
- gain adjustment
- electrically connected
- adjustment unit
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Abstract
A kind of signal synthesis circuit synthesizes the luminance signal that video signal source exports and carrier chrominance signal to export composite video signal.Signal synthesis circuit includes the first gain adjustment unit, delay unit and the second gain adjustment unit.First gain adjustment unit be used for receive video signal source output luminance signal and adjust received luminance signal gain.The luminance signal that delay unit is used to export the first gain adjustment unit carries out phase delay.Second gain adjustment unit be used for receive video signal source output carrier chrominance signal and adjust received carrier chrominance signal gain, synthesized with the luminance signal after delay to export composite video signal to tuner.Above-mentioned signal synthesis circuit substitution special signal synthesis chip synthesizes to realize the luminance signal to video signal source output with carrier chrominance signal, saves development cost.
Description
Technical field
The present invention relates to signal synthesis circuit more particularly to a kind of signal conjunctions for synthesizing luminance signal and carrier chrominance signal
At circuit.
Background technique
According to FCC (Federal Communications Commission)/CCIR (International Radio
Consultative Committee) organizational standard, the general set-top box with radio-frequency modulator, radio-frequency modulator output
The phase difference for meeting 170ns is needed between carrier chrominance signal and luminance signal included in composite video signal.Universal circuit design
It is the synthesis that signal is realized using existing dedicated signal synthesis chip, to meet FCC/CCIR standard, however, dedicated letter
Number synthesis chip unit price is higher.Therefore, a kind of signal synthesis circuit of low cost is designed to realize that output meets FCC/CCIR mark
Quasi- composite video signal becomes a big research topic.
Summary of the invention
In view of this, a kind of signal synthesis circuit need to be provided, development cost can be reduced.
Embodiment of the present invention provides a kind of signal synthesis circuit, luminance signal and color for exporting video signal source
Degree signal is synthesized to export to tuner, the signal synthesis circuit include the first gain adjustment unit, delay unit and
Second gain adjustment unit.First gain adjustment unit is used to receive the luminance signal and tune of the video signal source output
Save the gain of the luminance signal.The delay unit is electrically connected to first gain adjustment unit, for described first
The luminance signal of gain adjustment unit output carries out phase delay.It is single that second gain adjustment unit is electrically connected to the delay
Member, for receiving the carrier chrominance signal of video signal source output and adjusting the gain of the carrier chrominance signal, with the delay
Luminance signal afterwards is synthesized to export composite video signal to the tuner.
Preferably, the signal synthesis circuit further includes blocking unit, and blocking unit one end is electrically connected to described
The common end of two gain adjustment units and the delay unit, the other end are electrically connected to the tuner, and the blocking unit is used
In filtering out the DC influence signal in the luminance signal and/or the carrier chrominance signal.
Preferably, the blocking unit is first capacitor.
Preferably, first gain unit is first resistor, and one end of the first resistor is electrically connected to the delay
Unit, the other end ground connection of the first resistor.
Preferably, the delay unit includes the resonance circuit of multiple series connections.
Preferably, the delay unit include the second capacitor, third capacitor, the first inductance, the 4th capacitor, the 5th capacitor,
Second inductance, the 6th capacitor and the 7th capacitor.Second capacitor one end is electrically connected to first gain adjustment unit, another
End ground connection.The third capacitor is connected in parallel with second capacitor.First inductance one end is electrically connected to second electricity
Hold the common end with first gain adjustment unit.Described 4th capacitor one end is electrically connected to the another of first inductance
End, other end ground connection.5th capacitor is connected in parallel with the 4th capacitor.Second inductance one end is electrically connected to described
The common end of first inductance and the 4th capacitor, the other end are electrically connected to second gain adjustment unit and the tuning
Device.Described 6th capacitor one end is electrically connected to the common end of second inductance Yu second gain adjustment unit, the other end
Ground connection.7th capacitor is connected in parallel with the 6th capacitor.
Preferably, second gain adjustment unit includes second resistance and 3rd resistor.It uses described second resistance one end
In the carrier chrominance signal for receiving the video signal source output, the other end is electrically connected to the delay unit and the tuner.Institute
State the common end that 3rd resistor one end is electrically connected to the second resistance Yu the delay unit, other end ground connection.
Above-mentioned signal synthesis circuit replaces dedicated signal synthesis chip by the circuit that resistance, inductance and capacitor are constituted
Realization is synthesized and is exported with carrier chrominance signal to the luminance signal that video signal source exports, and development cost is saved.
Detailed description of the invention
Fig. 1 is the module map in one embodiment of signal synthesis circuit of the present invention.
Fig. 2 is the circuit diagram in one embodiment of signal synthesis circuit of the present invention.
Main element symbol description
Signal synthesis circuit 10,10a
Video signal source 20
Tuner 30
First gain adjustment unit 102
Delay unit 104
Second gain adjustment unit 106
Blocking unit 108
First to the 7th capacitor C1, C2, C3, C4, C5, C6,
C7
First to 3rd resistor R1, R2, R3
The first to the second inductance L1, L2
The present invention that the following detailed description will be further explained with reference to the above drawings.
Specific embodiment
Fig. 1 is the module map of signal synthesis circuit 10 in an embodiment of the present invention.In the present embodiment, signal synthesizes
Circuit 10 synthesizes the luminance signal that video signal source 20 exports and carrier chrominance signal to export composite video signal to tuning
Device 30 is transmitted to television set (not shown) after handling by tuner 30.Signal synthesis circuit 10 includes the first gain adjustment list
Member 102, delay unit 104 and the second gain adjustment unit 106.It is defeated that first gain adjustment unit 102 receives video signal source 20
Luminance signal out and adjust received luminance signal gain, to export the luminance signal of appropriate gain size.Delay is single
Member 104 is electrically connected to the first gain adjustment unit 102, and delay unit 104 believes the brightness that the first gain adjustment unit 102 exports
Number carry out phase delay, with export delay after luminance signal.Second gain adjustment unit, 106 one end is for receiving vision signal
The carrier chrominance signal that source 20 exports, the other end are electrically connected to delay unit 104.It is received that second gain adjustment unit 106 adjusts institute
The gain of carrier chrominance signal, to export the carrier chrominance signal of appropriate gain size to believe with the brightness after the delay of delay unit 104
It number is synthesized, to export composite video signal to tuner 30.In the present embodiment, delay unit 104 includes multiple
The resonance circuit of series connection, resonance circuit can be inductance capacitance (LC) resonance circuit.Luminance signal and coloration after delay
The phase difference of signal is 170ns, and the luminance signal of the phase difference and carrier chrominance signal are mixed into compound view by signal synthesis circuit 10
Frequency signal is simultaneously sent to tuner 30.
As a further refinement of the present invention, signal synthesis circuit 10 further includes blocking unit 108.Blocking unit 108
One end is electrically connected to the common end of delay unit 104 and the second gain adjustment unit 106, and the other end of blocking unit 108 is electrically connected
It is connected to tuner 30.Blocking unit 108 filters out DC influence signal present in luminance signal and/or carrier chrominance signal, thus real
Its DC influence signal for being included can be isolated when receiving composite video signal for existing tuner 30.
It should be noted that passing through the first gain adjustment unit 102 and the second gain adjustment list in signal synthesis circuit 10
When 106 gain to adjust luminance signal and carrier chrominance signal respectively of member, the size of gain adjustment can be according to actual design need
It asks to be set and be adjusted, it such as can be according to the model of the television set of composite video signal receiving end.
Fig. 2 is the circuit diagram of signal synthesis circuit 10a in an embodiment of the present invention.In the present embodiment, first increases
It includes first resistor R1 that benefit, which adjusts unit 102, and one end of first resistor R1 is electrically connected to video signal source 20, first resistor R1's
Other end ground connection.Delay unit 104 includes first capacitor C1, the second capacitor C2, third capacitor C3, the 4th capacitor C4, the 5th electricity
Hold C5, the 6th capacitor C6, the first inductance L1 and the second inductance L2.One end of first capacitor C1 is electrically connected to first resistor R1 and view
The common end of frequency source signal 20, the other end ground connection of first capacitor C1.Second capacitor C2 and first capacitor C1 is connected in parallel.First
One end of inductance L1 is electrically connected to the common end of first capacitor C1 Yu first resistor R1, and the other end of the first inductance L1 is electrically connected to
One end of third capacitor C3, the other end ground connection of third capacitor C3.4th capacitor C4 is connected in parallel with third capacitor C3.Second electricity
Sense one end L2 is electrically connected to the common end of the first inductance L1 Yu third capacitor C3, and the other end of the second inductance L2 is electrically connected to the 5th
One end of capacitor C5, the other end ground connection of the 5th capacitor C5.6th capacitor C6 and the 5th capacitor C5 is connected in parallel.Delay unit
104 can be by adjusting first capacitor C1, the second capacitor C2, third capacitor C3, the 4th capacitor C4, the electricity of the 5th capacitor C5 and the 6th
The inductance value for holding the capacitance of C6, the first inductance L1 and the second inductance L2 prolongs the phase of received luminance signal to adjust
Shi great little.
Second gain adjustment unit 106 includes second resistance R2 and 3rd resistor R3.One end of second resistance R2 is electrically connected
In video signal source 20, the other end of second resistance R2 is electrically connected to the common end of the second inductance L2 and the 5th capacitor C5.Third
One end of resistance R3 is electrically connected to the other end of second resistance R2, the other end ground connection of 3rd resistor R3.Second gain adjustment list
Member 106 can export the carrier chrominance signal of appropriate gain size by adjusting the resistance value of second resistance R2 and 3rd resistor R3.Every
Straight unit 108 includes the 7th capacitor C7.One end of 7th capacitor C7 is electrically connected to the public of the second inductance L2 and second resistance R2
End, the other end of the 7th capacitor C7 are electrically connected to tuner 30.Signal synthesis circuit 10 filters out compound view by the 7th capacitor C7
The DC influence signal that frequency signal is included.
It should be noted that existing in order to reduce the offset that the composite video signal of the output of signal synthesis circuit 10 is likely to occur
As resistance, inductance and the capacitor that signal synthesis circuit 10 is included are preferably the low accurate element of error, as error size is
1%.The first inductance L1 and the second inductance L2 is preferably DCR (direct current resistance) lesser inductance simultaneously
Element, such as DCR of the first inductance L1 and the second inductance L2 are 5m Ω.
Above-mentioned signal synthesis circuit replaces dedicated signal synthesis chip by the circuit that resistance, inductance and capacitor are constituted
Realization is synthesized and is exported with carrier chrominance signal to the luminance signal that video signal source exports, and development cost is saved.
Claims (5)
1. a kind of signal synthesis circuit, luminance signal and carrier chrominance signal for exporting video signal source are synthesized to export
To tuner, which is characterized in that the signal synthesis circuit includes:
First gain adjustment unit, for receiving the luminance signal of the video signal source output and adjusting the luminance signal
Gain；
Delay unit is electrically connected to first gain adjustment unit, bright for exporting to first gain adjustment unit
It spends signal and carries out phase delay；
Second gain adjustment unit is electrically connected to the delay unit, for receiving the coloration letter of the video signal source output
Number and adjust the gain of the carrier chrominance signal, to be synthesized with the luminance signal after the delay to export composite video signal
To the tuner；Wherein
The delay unit includes:
Second capacitor, one end are electrically connected to first gain adjustment unit, other end ground connection；
Third capacitor, the third capacitor are connected in parallel with second capacitor；
First inductance, one end are electrically connected to the common end of second capacitor Yu first gain adjustment unit；
4th capacitor, one end are electrically connected to the other end of first inductance, other end ground connection；
5th capacitor, the 5th capacitor are connected in parallel with the 4th capacitor；
Second inductance, one end are electrically connected to the common end of first inductance Yu the 4th capacitor, and the other end is electrically connected to institute
State the second gain adjustment unit and the tuner；
6th capacitor, one end are electrically connected to the common end of second inductance Yu second gain adjustment unit, another termination
Ground；And
7th capacitor, the 7th capacitor are connected in parallel with the 6th capacitor.
2. signal synthesis circuit as described in claim 1, which is characterized in that further include blocking unit, one end is electrically connected to institute
The common end of the second gain adjustment unit Yu the delay unit is stated, the other end is electrically connected to the tuner, for filtering out
State the DC influence signal in luminance signal and/or the carrier chrominance signal.
3. signal synthesis circuit as claimed in claim 2, which is characterized in that the blocking unit is first capacitor.
4. signal synthesis circuit as described in claim 1, which is characterized in that first gain adjustment unit is the first electricity
Resistance, one end of the first resistor are electrically connected to the delay unit, the other end ground connection of the first resistor.
5. signal synthesis circuit as described in claim 1, which is characterized in that second gain adjustment unit includes:
Second resistance, one end are used to receive the carrier chrominance signal of the video signal source output, and the other end is electrically connected to the delay
Unit and the tuner；And
3rd resistor, one end are electrically connected to the common end of the second resistance Yu the delay unit, other end ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410456447.XA CN105391959B (en) | 2014-09-09 | 2014-09-09 | Signal synthesis circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410456447.XA CN105391959B (en) | 2014-09-09 | 2014-09-09 | Signal synthesis circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105391959A CN105391959A (en) | 2016-03-09 |
| CN105391959B true CN105391959B (en) | 2019-04-02 |
Family
ID=55423741
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410456447.XA Expired - Fee Related CN105391959B (en) | 2014-09-09 | 2014-09-09 | Signal synthesis circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105391959B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3736370A (en) * | 1971-01-18 | 1973-05-29 | Gen Electric | Improved chroma clamping circuit |
| US5172217A (en) * | 1990-03-01 | 1992-12-15 | John Perkins | Transcoder for spatial manipulation of composite color television signals |
| CN1383332A (en) * | 2001-04-25 | 2002-12-04 | 汤姆森特许公司 | Video device and method for such video device and video recorder |
| US20030156228A1 (en) * | 2002-02-19 | 2003-08-21 | Samsung Electro-Mechanics Co., Ltd. | Radio frequency modulator having C/L delay compensation function, and set-top-box using the same |
-
2014
- 2014-09-09 CN CN201410456447.XA patent/CN105391959B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3736370A (en) * | 1971-01-18 | 1973-05-29 | Gen Electric | Improved chroma clamping circuit |
| US5172217A (en) * | 1990-03-01 | 1992-12-15 | John Perkins | Transcoder for spatial manipulation of composite color television signals |
| CN1383332A (en) * | 2001-04-25 | 2002-12-04 | 汤姆森特许公司 | Video device and method for such video device and video recorder |
| US20030156228A1 (en) * | 2002-02-19 | 2003-08-21 | Samsung Electro-Mechanics Co., Ltd. | Radio frequency modulator having C/L delay compensation function, and set-top-box using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105391959A (en) | 2016-03-09 |
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Granted publication date: 20190402 Termination date: 20200909 |