CN1125501A

CN1125501A - Filter by-pass for transmitting and additional signal with a video signal

Info

Publication number: CN1125501A
Application number: CN94192433A
Authority: CN
Inventors: 杰拉尔德·D·蒙哥马利
Original assignee: WavePhore Inc
Current assignee: WavePhore Inc
Priority date: 1993-06-14
Filing date: 1994-06-10
Publication date: 1996-06-26
Also published as: FI955972A; BR9406817A; WO1994030011A3; EP0705518A1; KR960703306A; WO1994030011A2; FI955972A0; JPH08511669A; CA2164830A1; AU7172394A

Abstract

The invention discloses a controlled element (27) for spectrum attenuation or a controlled filter is disclosed that is used to aid in the insertion of a secondary signal into a video signal without distorting the blanking intervals or close captioned data contained in the blanking interval of the video signal.

Description

Be used for transmitting the filter by-pass of additional signal with vision signal

The application is the part continuation application of 07/947, No. 134 U.S. Patent application of submission on September 18th, 1992, and the latter is the part continuation application of 07/748, No. 023 U.S. Patent application of submission on June 14th, 1991.The application also relates to the application submits on the same day and transfers the not following application of bohr (WavePhore) company of Wei: 08/076, No. 199 U.S. Patent application of my by name dynamic injection level control; 08/076, No. 196 U.S. Patent application of the DC level restoration of my modulator by name; And my 08/076, No. 137 U.S. Patent application that is used to transmit the timing signal of the secondary singal that has data by name.

The present invention relates to send a secondary signal, relate more specifically to send two signals with a vision signal with a vision signal.

Know that very early video spectrum does not effectively utilize in such as public commercial standards such as NTSC, PAL and SECAM.Though proposed some different standards in order more effectively to utilize this frequency spectrum, the high definition TV standard of most of standards such as the Japan in these standards etc. can not be received by traditional television receiver.

A kind of method of utilizing the frequency spectrum of vision signal more efficiently is the multiple multiplexed video signal of time-division that has data-signal.This is the method that is used for sending with vision signal closed caption data.Particularly, closed caption data is launched in vertical blanking interval.Custom-designed receiver can receive and show closed captioning information, and the more common receiver of buying can show the vision signal of transmission and be not aware of the interference of self-enclosed caption data.Yet the shortcoming of closed captioning television transmission data is that data rate is lower.

Utilize other scheme of video spectrum to comprise the residual sideband that utilizes luminance signal more efficiently.An example of this scheme has been shown in 4,958, No. 230 United States Patent (USP)s.In this patent, comb filter of effect on the intermediate frequency of the residual sideband of luminance signal.Then in this residual sideband one second luminance signal by frequency interleave.

Phase place and delay distortion that a shortcoming of these methods is filtering may come adverse effect to the blanking intervallum, thereby bring adverse effect to what send in these intervals such as data such as closed caption data.Comb filter described in 4,958, No. 230 United States Patent (USP)s may cause intersymbol interference and so on, thereby the reception of closed caption data is brought adverse effect.

In addition, this filtering also may influence the beginning and the end of vertical and horizontal blanking interval unfriendly.Though these influences can not cause the obvious quality of received signal to reduce, and may aware time-delay and phase distortion when the test transmission figure.Moreover this effect can cause detrimental effects to the test that sends signal.

This adverse effect is for being used to send the unfavorable especially such as coaxial quality test with various transmission links such as cable link, microwave relay link and satellite links of vision signal.The existence of this delay and phase distortion makes testing equipment and technical staff be difficult to differentiate that these consequences are to send the filter of additional signal or caused by transmission link by being used to.

Therefore, first purpose of the present invention is for providing a kind of system that more effectively utilizes the p high frequency spectrum.Second purpose of the present invention for provide more effectively utilize frequency spectrum do not disturb in blanking interval the substrate vision signal or such as the use of the transmission of other signals such as closed caption data.Another purpose of the present invention is for allowing the test of video transmission link.

These and other purpose is by utilizing the various filtering operations control among the present invention selectively to be adopted to reach.Particularly, at least in some part of some intervals of video, temporarily changed, disconnected or walked around the filter that is used for making up secondary and tertiary information and changes video spectrum at least certain some.This has eliminated the intersymbol interference in the blanking interval and the distortion of resolution chart, and has strengthened the test of network.

Bypass operation can be controlled by a controlled high impedance attenuator, a voltage-controlled filter of connecting with a bypass that centers on this filter or the controlled double-throw, the single knife switch that constitute around a bypass of this filter.The control lead-in wire of the Control Node of switch or attenuator or voltage-controlled filter is coupled to the control signal that is generated by a blanking detector.This blanking detector provides a control signal, makes attenuator or switch eliminate this filter effectively in blanking interval from circuit.

Fig. 1 is the block diagram of one embodiment of the present of invention.

Fig. 1 illustrates an embodiment of the signal processor of transmitter, and this transmitter can be used for also comprising simultaneously by the transmitter of the secondary data signal that constitutes such as closed caption data and launching numerical data signal 49 three times by having a basic NTSC colour-video signal 12.Other embodiments of the invention can be used for being used for not launching a secondary signal with the ntsc video signal of closed caption data and being used for launching secondary signal such as other video formats signals such as SECAN or PAL with launch the 3rd an additional analog signal with NTSC signal combination closed caption data together.

That the embodiment of Fig. 1 submitted on September 18th, 1992 with people such as Montgomery in fact and transfer Wei not the embodiment among Fig. 3 of 07/947, No. 134 U.S. Patent application of bohr company is identical, just omitted notch filter.The explanation of embodiment on 17 to 21 pages is quoted at this as a reference.In the embodiment in figure 1, secondary signal 49 is also modulated to be used for injecting at adder 70 places the output of video unit 20 by rasterisation (rasterize) by data cell 50.For the data-signal of the modulation that makes injection does not disturb the vision signal that offers modulator 56, the low pass filter 27 above above signal of vision signal, especially 3.7 megahertzes of chrominance carrier of decaying fully.This filter 27 resembles that the comb filter of being mentioned in top 4,958, No. 230 United States Patent (USP)s is the same can to cause phase distortion and different time-delays on input signal.Filter 27 also causes the frequency distortion of test signal, and these test signals substitute common TV programme and are played.

The difference of the embodiment of Fig. 3 of 07/947, No. 134 U.S. Patent application that people such as present embodiment and Montgomery submitted on September 18th, 1992 is comprising a filter bypass resistance 100.Filter bypass resistance 100 comprises a delay cell (not shown) that equals the time-delay duration of filter 27, and comprises a lead 112 and first lead of throwing 115 that is coupled to a single-pole double throw analog switch 110 on the input that is coupled to filter 27.The output of filter 27 also is coupling on the lead 113 that second of commutator 110 throws.The control end 114 of switch 110 is coupling on the output of OR-gate 116.The cutter of switch is coupling on the lead 119 that connects adder 70.

This switch is a high speed analog semiconductor switch preferably, such as what can buy from diversified different semiconductor makers.As an alternative, switch 110 also can be a controllable attenuator described below.

A time-delay composite blanking signal 117 that is provided as one of timing signal 54 is coupling on the control electrode 115 of switch 110 by OR-gate 116.The composite blanking signal 117 of this time-delay causes switch 110 to select bypass elements 100 rather than filter 27 during level and vertical blanking interval.Therefore, filter 27 is bypassed during blanking interval, therefore, the phase distortion or the frequency distortion of vision signal can not occur during level or vertical blanking interval.During blanking interval, there is not simultaneously any signal, such as closed caption data and perpendicular separation test signal by filter 27 effects yet.Thereby, at effective video between the departure date, the above video spectrum part of filter 27 decay 3.7 megahertzes same section of attenuation spectrum not then during blanking interval.

Though eliminated filter function during the blanking interval of vision signal, owing to only just there is the unfiltered part of vision signal not from the data with rasterized of the modulation of data cell 50 time, therefore the data and the vision signal of combination do not interfere with each other.Therefore, when the user watched TV programme and data just being transmitted, the Test Engineer can utilize the perpendicular separation test signal to observe unfiltered signal.

Control signal 118 also is provided for OR-gate 116 with control filters.This just allows the Systems Operator to walk around filter, and the Test Engineer can observe unfiltered resolution chart or identify performance with unfiltered vision signal at the transmission link test period when making the user not watch video frequency program.

Another input (not shown) can be coupling on the input of OR-gate 116, so that can walk around filtering when not having the data of transmission.In this case, IEEE 449 interfaces/rasterizer 51 generates another control signal (not shown) that is coupling on the OR-gate 116.When the buffer of interface/rasterizer 51 has emptied the sufficiently long time and sent all data, just generate this control signal and walk around filter 27.Walking around filter 27 continues up to the data that occur on the output of modulator 56 for transmission.

Substitute as another kind, do not adopt switch 110 to replace a controlled high impedance attenuator (not shown).In this case, causing the output of filter 27 to be provided for adder 70 in the impedance of effective video interim attenuator makes the output of filter bypass resistance 100 be provided during blanking interval.

In another kind substituted again, low pass filter 27 can replace with a voltage-controlled filter, eliminated whereby the needs of switch 110 with lead 113 and 115.In this case, the output of OR-gate 116 directly can be coupling on the voltage controlled bus, PV bus of filter, make the characteristic changing of filter to avoid phase distortion and the filtering during level and the video blanking interval.

As another kind of alternative again, may be a situation of only on certain effective video is capable, inserting three signals.For example, for some PAL version, it is desirable finding not use low pass filter 27 to allow some effective row of a frame to be sent.In these examples, for example in preceding 21 row of a frame, OR-gate 116 is not coupling on the composite synchronizing signal of time-delay.When not sending data, would rather determine data are added to the opportune moment of walking around filter 27 on the vision signal with the circuit (not shown).During the vertical blanking interval and do not send data during, will generate a control signal so that OR-gate 116 causes filter 27 to be bypassed.Only generate a control signal and filter is not bypassed during effective video in these row back.

Though embodiment above includes such as in the NTSC signal of secondary singals such as closed caption data at one three secondary data signal is added in, be familiar with present technique person and will be understood that the present invention also can be used in the normal NTSC signal of not being with the secondary data signal.Moreover embodiment above can be used for comprising in the PAL vision signal or SECAM signal of any version of closed caption data.Yet scope of the present invention is defined by claims.

Claims

1, a kind of processor is used for sending a secondary signal with an elementary video signal that has a kind of power spectrum and separate the capable blanking interval of effective video, and this processor comprises:

The blanking interval detector of a response vision signal; And

A controlled member, respond this blanking interval detector and during capable some part at least of effective video, at least an outputting video signal that has a part that obviously decays of video spectrum is provided on an output, and at least during some blanking interval, keep the same section of video signal spectrum unattenuated basically.

2, the processor of claim 1, wherein this processor also comprises:

A secondary units, the output of secondary signal being injected controlled member.

3, the processor of claim 1, wherein this controlled member also responds manual control and keeps described same section unattenuated basically, thereby further facilitates the test of a transmission link.

4, the processor of claim 1, wherein this processor comprises a secondary singal unit, this unit further provides an indication not have the absent signal of secondary signal; And

This controlled member responds this absence signal and does not decay.

5, the processor of claim 1, wherein this blanking detector also detects a predetermined space in the frame, and this controlled member does not provide decay basically in this predetermined interval.

6, the processor of claim 5, wherein this interval comprises preceding 21 row of a frame at least.

7, the processor of claim 1, thus wherein this controlled member comprises that the input of this element of a filter and one coupling walks around the gate-controlled switch of filter during blanking interval.

8, the processor of claim 1, thus wherein this controlled member comprises that a filter and one walk around this filter is walked around this filter during blanking interval changeable impedance path.

9, the processor of claim 1, wherein this controlled member comprises that one is coupled to respond the voltage-controlled filter of this blanking interval detector.

10, a kind of method with one first vision signal and one the 3rd signal combination, this first vision signal has a frequency spectrum and blanking interval, capable the separating of effective video that this blanking interval will be combined with a secondary signal that appears in first signal in only during the part of some blanking interval at least, this method comprises:

During not having some time interval of secondary signal, a part of frequency spectrum of this composite signal that decays; And

When having this secondary signal, the 3rd signal is injected composite signal.

11, the method for claim 10, wherein the 3rd signal only is injected in effective video interim.

12, the method for claim 10, wherein decay is to be finished by a filter of this composite signal of filtering, and wherein this method also was included in during the described time interval, walked around this filter.

13, a kind of method is injected into one with a secondary signal and has the rasterisation elementary video signal of separating the capable blanking interval of effective video, and this vision signal has brightness and chrominance information and a chrominance carrier, and this method comprises:

Detect the blanking interval of this vision signal;

At least during the capable part of some effective video, a part of vision signal significantly decays;

Secondary signal is injected the video line part of decay; And

Do not add decay and do not inject secondary signal, transmit the blanking interval part of this vision signal.

14, the method for claim 13, wherein this detection is finished by a digital video signal processor with decay.

15, the method for claim 13, wherein this decay is to be finished by a filter that is bypassed during blanking interval.

16, the method for claim 13, wherein the part of this decay comprises the portions of the spectrum that chrominance carrier is above.

17, a kind of device, being used to handle an input signal provides an output signal, and this device comprises:

A controlled selector has two at least and selects input, an output and a Control Node, and a kind of condition of response Control Node is coupled to one of input on the output selectively;

A filter element responds this input signal and is coupled to and one of selects in the input; And

A bypass elements responds this input signal and is coupled to another and selects on the input.