JPH0112453Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mixing circuit, and in particular, to a mixing circuit that can produce various video effects by controlling and mixing a plurality of video signals such as television signals. This is suitable for application to effect devices.

[Background technology and its problems]

This type of mixing circuit includes the ADD MIX system, the NON ADD system, and the NON ADD MIX system.
(MIX) system, etc., and the configuration shown in FIG. 1 has conventionally been used as a NUMIX system mixing circuit. In Figure 1, 1
A and 1B are the first and second video signals, respectively.
This is a multiplier circuit that receives A _IN and B _IN , and fader control signals FA and FB are applied to its variable gain control terminals, respectively. fader control signal
FA and FB are set to the second position according to the operation of the fader lever.
It changes from 0% to 100% (or vice versa) as shown in the figure. Here, the fader lever passes from 0% position P (0%) to 50% position P (50%).
When operated to change to 100% position P (100%), the first fader control signal
FA maintains a value of 0% when the fader lever is at the P (0%) position, and then changes from 0% to 0% when the fader lever position changes from P (0%) to P (50%). It increases linearly to 100%, and then the fader lever position changes to P (50%).
%) to P(100%) and accordingly
The value is maintained at 100%. On the other hand, the second fader control signal FB maintains 100% output when the fader lever is at P (0%), and then changes from P (0%) to P (50%). When the fader lever position changes from P (50%) to P (100%), it will still maintain the 100% value, and will linearly decrease from the 100% value to the 0% value. When the fader lever position reaches P (100%), the value of 0% is maintained.

Thus, the outputs A1 and B1 of the multiplier circuits 1A and 1B convert the levels of the video signals A _IN and B _IN into video signals that change in accordance with changes in the fader control signals FA and FB applied to the multiplier circuits 1A and 1B, respectively. Sent out. This is the second
As shown in the figure, the fader lever is set to P.
(0%) to P (50%), one video signal A1 follows the change in fader control signal FA and changes from 0% to 100%, while the other video signal B1 changes from 0% to 100%. This means that the fader control signal FB continues to maintain its 100% value without changing. In addition, when the fader lever position changes from P (50%) to P (100%), the video signal B1 changes to follow the fader control signal FB as it changes from 100% to 0%. On the other hand, since the fader control signal FA maintains a value of 100%, the other video signal A1 follows this and maintains a value of 100%.

These video signals A1 and B1 are given to a selection output circuit 2. This selection output circuit 2 outputs the video signal of the higher level of the two arriving video signals A1 and B1 from the mixing circuit.
Send as M _OUT . Thus, the content of the mixing output signal M _OUT becomes the video signal B1 when the fader lever is at the 0% position P (0%), and the content of the mixing output signal M OUT becomes the video signal B1 when the fader lever is at the 0% position P (0%);
%) to P (50%), the fader control signal FA changes from 0 to 1.0, causing the video signal A _IN・FA and the video signal B1
(= B _IN ), and after passing the 50% position P (50%), the fader control signal FB changes from 1.0 to 0, causing the video signal B _IN / FB and the video signal A1 (=A _IN ), whichever has the greater level. As a result, when the fader lever is operated from 0% to 100%, the fader control signals FA and FB will change when the fader lever reaches 50%.
When passing the % position P (50%), FA = 0 to 1.0,
This fader control signal is switched from the state of FB = 1.0 to the state of FA = 1.0 and FB = 1.0 to 0.
Among the video signals obtained by multiplying the video input signals A _IN and B _IN by FA and FB, respectively, the video signal with a higher level is output as the mixing output M _OUT .

By the way, in the conventional configuration shown in Fig. 1, changes in the fader control signals FA and FB change in an asymmetrical relationship with respect to the operating position of the fader lever, so when multiplying the video input signals A _IN and B _IN by this, Multiplication was performed using separate multiplication circuits 1A and 1B, respectively. However, in this case, it is essential to provide two sets of multiplier circuits, and there is a certain limit to the simplification of the overall structure. In addition, in order to obtain a mixing output signal M _OUT whose contents are switched accurately, it is necessary to prepare multiplier circuits 1A and 1B with the same linearity, and it is actually very difficult to fully satisfy such requirements. Since it is necessary to prepare a material that is difficult and has good characteristics, it is unavoidable that it will be expensive.

[Purpose of invention]

This idea was created taking the above points into consideration.
The present invention attempts to improve the above-mentioned problems by requiring only one multiplication circuit for multiplying a video input signal by a fader control signal.

[Summary of the idea]

The present invention is a mixing circuit that switches and outputs an input video signal in response to a fader operation of a fader lever, and switches the selection of the input video signal input to a multiplier circuit when the fader lever passes a predetermined switching operation position. Accordingly, it is possible to provide only one multiplication circuit.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 3, the video input signal A _IN is applied to the input terminals a1 and a2 of the two selection circuits 11 and 12, and the video input signal B _IN is applied to the input terminals a2 and a1 of the selection circuits 11 and 12. A fader lever detection signal S11 is applied to the selection circuits 11 and 12 as a selection control signal. This fader lever detection signal S11 indicates that the fader lever is 0.
% to 50%, selection circuits 11 and 12
is connected to the input terminal a1 side, and when the selection circuits 11 and 12 are at the 50% to 100% position, are connected to the input terminal a2 side. As a result, the selection circuits 11 and 12 select the video input signals A _IN and B _IN respectively when the fader lever is between 0% and 50%.
12 and S13, and when the fader lever is at the 50% to 100% position, the video input signals B _IN and A _IN are respectively selected as the output signal S1.
2 and S13. Thus, the selection circuits 11 and 12 are configured to switch the contents of the selection output signals S12 and S13 to each other each time the fader lever passes the 50% position.

Further, fader control signals FA and FB are given to input terminals a1 and a2 of the selection circuit 13,
When the fader lever is between 0% and 50% according to the fader lever detection signal S11, the fader control signal FA is selected and outputted through the input terminal a1.
14, and the fader lever is 50% ~
When it is at the 100% position, the selection circuit 13 selects the fader control signal FB through the input terminal a2 and sends it out as the selection output S14.

In this way, the selection output S12 containing the video input signal A _IN or B _IN obtained from the selection circuit 11 is given to the multiplier circuit 14, and the selection circuit 13
Fader control signal FA obtained at
Alternatively, the selection output S14 containing FB is given to the multiplication circuit 14 and multiplied, and the multiplication output S1
5 is applied to the input terminal a1 of the selection circuit 16 constituting the selection output circuit 15. On the other hand, the selection output S13 of the selection circuit 12 is applied to the other input terminal a2 of the selection circuit 16. In addition, the selection output circuit 15 is provided with a comparison circuit 17, which connects the multiplication output S15 of the multiplication circuit 14 and the selection output S13 of the selection circuit 12 to comparison input terminals a1 and a, respectively.
2, when the comparison input S15 of the comparison input terminal a1 is larger than the comparison input S13 of the comparison input terminal a2, the selection circuit 16 is switched to the terminal a1 side, and the comparison input S13 of the comparison input terminal a2 is set to the comparison input terminal a.
When it is larger than the comparison input S15 of 1, the selection circuit 16
A selection control signal S16 is sent to switch the terminal to the terminal a2 side. Thus, the selection output circuit 15 is the multiplication circuit 1
The multiplication output S15 of 4 is the selection output S of the selection circuit 12.
When the level of the selection output S13 is higher than the level of the multiplication output S15, the multiplication output S15 is sent out as the mixing output signal _MOUT through the selection circuit 16, and conversely, when the level of the selection output S13 is higher than the level of the multiplication output S15, the selection output S13 is sent out as the mixing output signal MOUT through the selection circuit 16. Send as signal M _OUT .

In the above configuration, when the operation position of the fader lever is between 0% and 50%, the selection circuit 11 receives the video input signal.
A _IN is sent out as the selection output S12, and the selection circuit 12 is in a state where it sends out the video input signal B _IN as the selection output S13. At this time, the selection circuit 13 is in a state where the fader control signal FA is given to the multiplication circuit 14 as the selection output S14, and thus the multiplication output S15 of the multiplication circuit 14 is the video input signal.
This is the result of multiplying A _IN by the fader control signal FA. However, when the fader lever position is in the range of 0% to 50%, the value of the fader control signal FA is between 0% and 100%.
Therefore, the value FA・A _IN of the output S15 of the multiplier circuit 14
will be between 0% and 100%. On the other hand, the value of selection output S13 is 100% value B _IN , but the value FA・
By comparing the levels of A _IN S12 and the value B _IN S13, the mixing output signal M _OUT becomes the one with the higher level.

Eventually, when the fader lever operation position exceeds 50% and moves toward 100%, the selection circuits 11, 12, and 13
Since the switching operation is performed when passing the 50% position, the multiplier circuit 14 is given the video input signal B _IN through the selection circuit 11 and the fader control signal FB from the selection circuit 13, and thus the contents of the multiplication output S15. becomes FB・B _IN . On the other hand, the value of the output S13 of the selection circuit 12 becomes the video input signal A _IN . However, when the fader lever is in this position, the fader control signal FB
The value of is between 100% and 0%, while the video input signal A _IN is at 100%, but by comparing the levels of the value A _IN S13 and the values FB and B _IN , the mixing output The signal M _OUT has the higher level.

In addition, in the above, the fader control signal
FA or FB is at the 50% operation position of the feda lever.
Although the case has been described in which the switching point reaches a value of 100% or starts to decrease from that value, the operating position of this switching point can be arbitrarily selected as required.

[Effects of the invention] As described above, according to the invention, a mixing output signal having a nummix function can be obtained with a simple configuration using only one multiplier circuit.
Therefore, it is possible to obtain a mixing circuit which has a simpler configuration than the conventional configuration shown in FIG. 1, and which does not have the conventional problem of making the characteristics of two multiplier circuits equal.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional nummix mixing circuit, Fig. 2 is a signal waveform diagram showing a fader control signal used in the nummix mixing circuit, and Fig. 3 shows an embodiment of the mixing circuit according to the present invention. FIG. 11, 12, 13, 16... selection circuit, 14...
...Multiplication circuit, 15...Selection output circuit, 17...Comparison circuit.

Claims (1)

[Claims for Utility Model Registration] While the fader lever is operated from the first operating position to the second operating position, the level of the first input video signal or the second input video signal is adjusted depending on the position of the fader lever. The first and second input video signals are input to a mixing circuit that outputs a signal with a higher level after controlling
The first input when the fader lever is in a first fader operation range from the first operation position to a predetermined switching operation position in response to a selection control signal formed based on the operation position of the fader lever. Selecting and outputting a video signal, and selecting and outputting the second input video signal when the fader lever is in a second fader operation area from the predetermined switching operation position to the second operation position. a first selection circuit to which the first and second input video signals are input;
When the fader lever is in the first fader operation area according to the selection control signal, the second
a second input video signal that selects and outputs the input video signal, and selects and outputs the first input video signal when the fader lever is in the second fader operation area;
a selection circuit for multiplying the output signal of the first selection circuit by a fader control signal whose level changes depending on the position of the fader lever; a selection output circuit that outputs a signal having a higher level among the output signals of the circuit as a mixing output signal;
The level increases when the fader is operated through the fader operation area to the above-mentioned predetermined switching operation position,
The feeder lever passes from the predetermined switching operation position to the second feeder operation area.
A mixing circuit characterized in that the level decreases when the operating position is reached.