JPS5851680A - Subcarrier phase adjusting circuit - Google Patents

Abstract

PURPOSE:To simplify the operation and to prevent mis-operation, performing accurate phase adjustment with small size, by adjusting the phase purely electronically in use of a mixing circuit. CONSTITUTION:Two subcarriers with different phase are applied from input terminals 11-14, 21-24, a plurality of circuits M1-M4 mixing the subcarrier are connected in series in the ratio corresponding to a bias voltage, the bias voltage is applied in common to terminals 41-44 of the circuits M1-M4, a variable voltage is applied to terminals 51-54 so that the circuits M1-M4 can mixingly be operated in the range of different bias voltage. Thus, the phase of the subcarrier can be adjusted to an arbitrary phase by adjusting the variable bias voltage with a variable voltage source VR.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a subcarrier phase adjustment circuit suitable for remotely controlling the phase of subcarriers when synchronizing video signals from a plurality of television cameras.

When video signals from multiple television cameras are switched and a captured scene is spliced together, each video signal must be in phase. %.

In the case of a color video signal, if the subcarriers are not in phase, colors may shift or be lost every time the scene changes. This phase shift of the subcarriers is caused by the difference in cable length for transmitting the output video signals from each television camera.

Therefore, a subcarrier phase adjustment circuit is provided to adjust the phase of the subcarrier for each output video signal of each television camera, so that the phase of the subcarrier can be adjusted depending on the length of the cable used. In a television camera in which this subcarrier phase adjustment circuit is provided in the camera head and the video signal and subcarrier from the camera head are supplied to a color coder, a control signal is sent from a remote control device to the subcarrier phase adjustment circuit via a cable. The phase of the subcarriers can be adjusted by remote control. In such a television camera,
From the viewpoint of camera operation, it is necessary to reduce the number of cables as much as possible.

FIG. 1 is an explanatory diagram showing an example of a conventional subcarrier phase adjusting device, in which subcarriers of phase O° are supplied to coils CL, , CL, and coils CL, , CL.

By supplying a subcarrier with a phase of 90@ to generate orthogonal alternating magnetic fields F, , F, and providing the sense coil C8 rotatably through 360 degrees within the magnetic field, it is possible to generate an arbitrary phase from the sense coil C8. This makes it possible to obtain subcarriers. However, this device requires a mechanical system to rotate the sense coil C8.
When this is attached to the camera head, the disadvantage is that the two heads of the camera become unreasonably loud.

FIG. 2 is a circuit diagram showing an example of a conventional subcarrier phase adjustment circuit using a variable delay circuit, in which a plurality of coils L connected in series and a plurality of variable capacitance diodes D connected in parallel are used.
It is possible to change the capacitance of the diode D using a control signal supplied from the terminal 3 to change the delay amount of the subcarrier supplied from the input terminal 1, and to obtain a subcarrier of an arbitrary phase at the output terminal 2. It has been made possible. However, this subcarrier phase adjustment circuit has a drawback that the temperature of the coil L has a large influence, which causes a phase error.

FIG. 3 is a circuit diagram showing still another example of a conventional subcarrier phase adjustment circuit using mixing means, and is a circuit diagram showing input terminals 1 and 2.
, 3, 4, the phases are 0°, 90°, and 180″, respectively.

A 270° subcarrier is provided to the fixed terminal of each switch S, , S,. Switches S, , S, are switched in conjunction with each other, and as a result of their switching, the phases θ° and 90', 90° and 180'', 180@ and 2 are changed from the respective movable terminals.
700 or 2701 and O@(360") are obtained. The subcarriers from switches S, , S, are supplied to a mixing circuit M, and a mixed signal mixed at a ratio according to the movable contact is output to the output terminal. 5.

In this conventional example, the subcarriers U and U obtained in the switches S, S, are 111 = all ((al is 10,) ul = sis
(ωt+θl) When the mixing ratio of the mixing circuit M is a:b, the output of the mixing circuit M, that is, the subcarrier U obtained at the output terminal 5 is as follows.

u=au, +bu.

== m sin (ωt + 1) + b sin
(*t + #t); v+bself+2
1ba+s(θ1-θ, )By the way, Jl-θ,=
Since the angle is 90°, equation (1) becomes as follows.

Therefore, if a subcarrier with a phase of θ is mixed with a subcarrier with a phase shift of 90'' from this in a ratio of 'kb:a', one phase will be 0m +ta-' (a
lb) subcarriers will be obtained. and,
-■(alb) changes between θ°90° depending on the ratio b:a. Therefore, if switch Sl is switched so that a subcarrier with phase θ'' is obtained, 90
Since the subcarriers of ° are obtained and θ,=01.

By changing the mixing ratio of the mixing circuit M, a subcarrier with an arbitrary phase from 0° to 90° can be obtained at the output terminal 5, and similarly, a subcarrier with a phase of 90° can be obtained at the switch S. When switching to , θF is 0, so
Subcarriers with any phase from 90° to 1806 can be obtained, and if switch 8I is switched to obtain subcarriers with a phase of 180°, since θ = 1800, any phase from 180@ to 2706 can be obtained. subcarriers are obtained, and furthermore, the subcarriers of switch S.

When switched to obtain a subcarrier with a phase of 270°, 0. Since it is ±270°, 270' to 36
Subcarriers with arbitrary phases up to 00 can be obtained. Therefore, by operating the switches 8I, 8- and the mixing circuit M, subcarriers of any phase can be obtained.

In this conventional example, since a variable delay line is not used, there is no drift due to temperature, and errors are less likely to occur. However, there are two operation parts, one for the switch 819 and the other for the mixing circuit M, and if this subcarrier phase adjustment circuit is installed in the camera head for remote control, a minimum of two control signal transmission cables are required for this purpose. It becomes necessary and again.

Using one cable has the drawback that it requires a thick cable, making it difficult to operate the television camera. Furthermore, the subcarrier phase adjustment (b) path requires manipulation at two locations, which is cumbersome, and there is a risk of erroneous manipulation.

The object of the present invention is to eliminate the drawbacks of the above-mentioned prior art.

A wide range of subcarrier phase adjustment is possible with only one operation unit, and the operation is easy and there is no risk of erroneous operation. For remote control, a thin and lightweight control signal transmission cable can be used. The present invention provides a subcarrier phase adjustment circuit.

To achieve this objective, the present invention provides two
A plurality of circuits are connected in series to which one subcarrier is supplied and mix the subcarriers at a ratio according to the value of the bias voltage, and the bias voltage is commonly supplied to these circuits. are characterized in that they are pressed to perform mixing operations in different ranges of the bias voltage.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 is a block diagram showing an embodiment of the subcarrier phase adjustment circuit according to the present invention, and is 1+11*@Im*
14 *2+ s2* *2s, 24 is the input terminal,
3 is the output terminal.

4. 4. ．． 4j, 4. is a constant bias voltage supply terminal, 51-5=, 58-54 is a variable bias voltage supply terminal, Ml + Ma vM, , M is a mixed circuit *e+
let He@, e, is a constant voltage source.

Next, the operation of this embodiment will be explained.

In the same figure, the mixing circuit M receives a subcarrier of phase 0° from input terminal II, and a subcarrier of phase 9° from input terminal 2I.
A 0° subcarrier is supplied, and its output signal is supplied to a mixing circuit M from one input terminal. The mixing circuit M also has an input terminal 2. A subcarrier with a phase of 180" is supplied from the input terminal 1, and its output signal is supplied from the input terminal 1 to the mixing circuit M. The mixing circuit M further has an input terminal 2.
．． A subcarrier with a phase of 270° is supplied from the input terminal 14, and its output signal is supplied from the input terminal 14 to the mixing circuit M.

The mixing circuit section further has a phase of 360° (0
@) subcarrier is supplied, and its output signal is supplied to the output terminal 3.

On the other hand, as a bias voltage applied to the mixing circuit M, ,M, ,M, ,M, from a constant voltage source e, terminal 4.
[The constant voltage island is connected from the constant voltage source e, let to terminal 4.
A constant voltage E, -1-E is applied to a constant voltage e, , e so, e
, from terminal 4° to constant voltage E, Toshima +E-1, and again. Constant voltages E, +E, +E, +E are applied from the constant voltage source e and C4 to the terminal 46, and a variable voltage VK is applied from the variable voltage voltage VR to the terminals 51.5□5m and 5m in common. , is applied.

Now, the voltage magnitude relationship is Va<V<V-<Va
<V-torto, variable pressure Vli to 0 color V+,
Vm*Va, Vm, Vl When changing with power supply voltage.

When vI≧Vz, the mixed circuit area, 凰, 凰, and 凰 are respectively connected to input terminals 1. *1*L 1. , 14, and when v snow≧−vE≧v1, the mixing circuit M@ outputs the signal from the input terminal I
I.

The mixing circuits M, , M output a signal mixed at a mixing ratio according to the signal from 2I or E.

M outputs the signals from input terminals 1m-1at14, respectively;
The mixing circuit M outputs the signal from the input terminal, 2.
The mixing circuits M, , M output a mixed signal according to VB, and the mixing circuits M, , M, respectively have input terminals 1m, 1. outputs a signal from 9 to the mixing circuit when -≧VE≧V,
Ml outputs the signals from the input terminals 2+t2*, the mixing circuit M outputs the signals from the input terminals 1m12m, which are mixed at a mixing ratio according to E, and the mixing circuit 凰 outputs the signals from the input terminals 14. output a signal.

When V1≧■≧η, the mixing circuits M, , M, , M have input terminals 21, 2□2. Mixing circuit 凰 outputs a signal obtained by mixing the signal from input terminal 1i*2* with a mixing ratio according to ■8, VIEW V, Notoki, mixing circuit M,, M,, M ,
, M,)'! -Each input terminal 2*-2 snow @ 2s-2
Set the voltage &s&*EaVs*N#v, , V, , V, to output the signal from -. Here, the mixed circuit M, , M.

The configurations of M, , Ml are made the same, and each bias voltage is determined so that each operation is performed as described above.

Therefore, the above-mentioned mixed circuits M, , M, , M.

According to the operation by the variable bias voltage yi of the elbow.

At the output terminal 3 of the subcarrier phase adjustment circuit, Vl≧V
E, input terminal 1. The subcarrier with a phase of 0° from the input terminal L@2+ is
When the mixed signal by mixing circuit M1 of subcarriers with phase 90° and 90" is ■, ≧■≧■, the mixed signal produced by mixing circuit wlIm of subcarriers with phase 90° and 18°0" from input terminal 2+12m is When , ■, ≧■≧V, a mixed circuit M of subcarriers with phases of 180° and 276° from the input terminal 2x e2@.

Mixed signals due to.

(2) When ≧VE≧V, a mixed signal from the input terminal 2tt2m is generated by the mixing circuit M of subcarriers with phases of 180° and 270°.

When vl≧VE≧■4, the mixed signal from the input terminal 21@24 by the mixing circuit M4 of subcarriers with phases of 270° and 360' (0°) is further added to the input terminal when ■E≧V, Phase 360° from 24 (
0°)Q) subcarriers will be obtained.

By the way, the mixing circuits M, , M, , M, , M4 do not operate so that the signal from one input terminal directly becomes the output signal, but when they mix the signals from the two input terminals. When performing a mixing operation to output, since the two input signals have a phase difference of 90 degrees, each input signal (F!r) is -θ1.θ.

+90@, the output signal is expressed by the above equation (2).

Therefore, since θ is Oo in the mixing circuit M, the output signal during the mixing operation is a subcarrier with an arbitrary phase from 09 to 90'' depending on the variable voltage VEK, and similarly, the mixing circuit In MdC, θ is 90'', so its output signal is a subcarrier with an arbitrary phase from 907 to 180°, and in mixing circuit M, θ is
, is 1800, the output signal is a subcarrier with an arbitrary phase from 180° to 270°, and in the mixing circuit M, R1 is 270@, so the output signal is a subcarrier with an arbitrary phase from 270° to 360°. (It is a subcarrier of any phase up to O. Therefore, by adjusting the variable bias voltage VE in the variable voltage source vR, it is possible to obtain a subcarrier of any phase from 0° to 360°, i.e. , one phase of subcarrier 06 to 360 @
can be adjusted to any phase.

Next, the specific circuit configuration of the mixing circuits M, , M, , K, and 凰 in FIG. 4 will be explained.

FIG. 5 is a circuit showing an embodiment of the above-mentioned mixing circuit,
Since each mixing circuit has the same configuration, the fourth
The parts corresponding to the figure are given the same number with the suffix removed, and R0 horse, R,, R14, RI are resistance (,1
,,C, is a capacitor, TR,,TR,,Tmelon.

TRI 'I'["RI is a transistor, and 7 is the output terminal of the mixing circuit. In this example, the transistor TR
, or TR.

An NPN type transistor is used, and the transistor TR
. ,,
TR, is also coupled differentially, and the phase θ is connected to the emitter from the input terminal 2 to the capacitor C, yri+1 to the base.
Transistor 1 supplied with +90° subcarriers
゛・Turtle collectors are commonly connected. The emitters of the transistors TR, , TR, are grounded via resistors R, , R, respectively, and a constant voltage Vq is applied to their bases via a resistance ratio, . transistor TR
A constant voltage Vp is applied to the collectors of the transistors TR, TR4, and a constant voltage Vp is applied to the collectors of the transistors TR, TR4 via a load resistor.

Further, a constant voltage E from a voltage source e is applied to the bases of the transistors Tl(,,TR,) via a terminal 4.

In addition, the bases of the transistors TR, TR, are connected to the terminal 5.
A variable voltage Vm from a variable voltage source VR is applied via the variable voltage source VR.

Next, the operation of this mixing circuit will be explained.

In the same figure, if the voltage E of the voltage source e is set to a predetermined value, the voltage value lower than the voltage E by an arbitrary voltage is Va, and the voltage value that is lower by an arbitrary voltage is vb, then the variable voltage source VR
The mixing circuit operates as follows depending on the value of the voltage VE.

When the voltage E and the voltage yi are compared and the voltage VK is Va≧E, the transistors TR, TR1+; ONL and the transistors TR, TR and T are turned off.

As a result, the transistor TR is connected to the input terminal 1.

The current that changes depending on the subcarrier of phase θ, supplied to 5 load resistances is about 1. Since the current that changes due to the subcarriers of the phase θ 90'' supplied from the input terminal 2 to the transistor T& flows through the transistors TR, , TR, the output terminal 7 Phase θ supplied to input terminal 1.

subcarriers are obtained.

Comparing voltage E and voltage VE, voltage VE is vb≧VIC
When ≧Va, the transistors T, TR, and TR, .
TR, . operates as a differential circuit with the same ratio according to the voltage VKV.

As a result, the current that changes depending on the subcarrier of phase θ supplied from input terminal 1 is
. ．． TR, is distributed in the same ratio. And transistor TR,...
Since the collector current of TR is mixed and flows through the load resistor R, a signal is obtained at the output terminal 7 in which the phases θ1 and θ, +90°C subcarriers are mixed at a ratio corresponding to the voltage Vic. 2) As shown in the formula, from 08 to θ*
Subcarriers of arbitrary phase can be obtained according to the voltage VE from -1 to 90 degrees.

Comparing voltage E and voltage VW, voltage VIC is vg, 2v
When b, transistors TR, , TR, are turned on.

Transistor TI (,, T circle is 0FFf.

As a result, from the input terminal 1 to the transistor TI(.

The current that varies depending on the subcarrier of phase θ, supplied to the transistors TR, TR.

The current flowing through the load resistor RI and changing due to the +90° subcarrier of phase θ supplied to the transistor TR, from the input terminal 2 is
, so that the subcarrier of phase 1 θ, +90@, which is supplied to the input terminal 2, is obtained at the output terminal 7. In this way, the voltage VE from the mixing circuit causes θ, to θ, +90”
This mixing circuit will obtain an arbitrary phase of S2-=IP up to θ.

20'' -V a = V * Vb - V * One example is the mixed 11 path M in Figure 4, where θ, = 90°, Va
=V, , Vb =■, is the same mixed circuit M
, and θ.

= 180°, Va = Vs, Vb = V4"C'
There is also a mixed circuit M, and θ,=2
70°, Va=V4. Similarly, the mixing circuit M has vb=v.

FIG. 6 is a circuit diagram showing another embodiment of the mixing circuit of FIG. 4, which is different from the embodiment shown in FIG.
, R, are respectively provided between the emitter of the transistor '['R,, TR, and the collector of the transistor TR, and between the emitter of the transistor TR,, TR, and the collector of the transistor 1'R1. Other than that, the configuration is the same and the operation is also the same, so the explanation will be omitted.

FIG. 7 is a circuit diagram showing still another embodiment of the mixing circuit of FIG. 4, in which a transistor TR, which directly differentially operates subcarriers of phase θ from the input terminal 1.

to the emitter of TR, and from input terminal 2 to the phase 0°+
The 90° subcarriers are directly supplied to the emitters of the differentially operated transistors TI (,,,TR,), and the output terminals 7 to 6, which are commonly connected to the collectors of the transistors TR, ,'l'R, to Ot+9° 8 is a circuit diagram showing still another embodiment of the mixing circuit shown in FIG. 5. In contrast to the mixing circuit shown in FIG. A variable voltage is applied to the transistor TR, TR, and the transistor TI (, .

The configuration is the same except that a constant voltage is applied to the pace of TR, and the operation is similar, so the explanation will be omitted.

FIG. 9 is a circuit diagram showing still another embodiment using PNP type transistors of the mixed circuit of FIG. 4, in which, similarly to the embodiment shown in FIG. , ,TR, and 'rR, ,'I', and further explanation will be omitted.

Note that the reference numerals used in the embodiments shown in FIGS. 6 to 9 are the same as those of corresponding parts in the embodiment shown in FIG.

As explained above, according to the present invention, the switch Iol
Since the phase is adjusted purely electronically using a mixing circuit without installing a circuit, it is small and allows accurate phase adjustment without temperature drift or noise.

Since there is only one operating part for adjustment, operation is easy and the possibility of erroneous operation is reduced, and remote control is also easy, and the cable for transmitting control signals for this purpose can be of a small diameter and has a small diameter. %, attaching the above cable to the television camera will not interfere with the operation of the camera.Furthermore, the production process will be reduced since the multiple mixing circuits used will have the same configuration. It is possible to use a mixing circuit with precisely matched characteristics, and it is possible to provide a subcarrier phase adjustment circuit with excellent functions at a low cost, while eliminating the drawbacks of the prior art.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one conventional example of a subcarrier phase adjustment device, FIG. 2 is a circuit diagram showing one conventional example of a subcarrier phase adjustment circuit, and FIG. 3 is a circuit diagram showing another conventional example. FIG. 4 is a block diagram showing an embodiment of the subcarrier phase adjustment circuit according to the present invention, FIG. 5 is a circuit diagram showing an embodiment of the mixing circuit, and FIGS. 6 to 9 are block diagrams showing other embodiments of the mixing circuit. FIG. 2 is a circuit diagram showing an example. 1+-1*e 1s* 1412112*e 2s*
24...Input terminal. 3...Output terminal, M,, M,, M,, M4・
...Mixed circuit. VR-...Variable voltage source, R1...Load resistance Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] (1) Phases are 0° and 90@1180@1360, respectively.
In a subcarrier phase adjustment circuit that is supplied with subcarriers of 0° and can obtain subcarriers with any phase of 01 to 360° by changing the bias voltage, the subcarriers with one phase of 0° and 90° are used. a first mixing circuit that is supplied, a second mixing circuit that is supplied with the subcarrier whose phase is 180@ with respect to the output signal of the first mixing circuit, and an output signal of the second mixing circuit; a j-th mixing circuit to which the subcarrier with a phase of 270° is supplied; and an output signal of the third mixing circuit with a phase of 36°.
a fourth mixing circuit to which the subcarrier of 0° is supplied, and a variable voltage source having means for commonly supplying a bias voltage to the first to fourth mixing circuits and for changing the bias voltage; and the phase of the output signal of any one of the first to fourth mixing circuits changes depending on the value of the bias voltage, and the output signal is transmitted from the fourth mixing circuit to the sub-channel of the arbitrary phase. A subcarrier phase adjustment circuit characterized in that it is configured such that it can be obtained as a carrier. (23%) In claim 1, each of the first to fourth mixing circuits has means for mixing two input signals supplied thereto at a ratio corresponding to the value of the variable bias voltage. , the subcarrier phase adjustment circuit is configured to be able to generate the output signal whose phase changes between the phases of the two input signals. (3) In claim 2, the first to The fourth mixing circuit includes first and second transistors whose emitters are commonly connected and whose emitters are supplied with one of the two input signals, and whose emitters are commonly connected and whose emitters are supplied with one of the two input signals. a third and a fourth transistor, the other being supplied with a load resistor commonly connected to the collectors of the second and fourth transistors, and a bias that is common to the pace of the first and fourth transistors; and means for commonly supplying another constant bias voltage to the collectors of the second and fourth transistors via the collectors of the first and third transistors and the load resistor. , said first
A subcarrier phase adjustment circuit characterized in that the first to fourth transistors are NPN transistors, and are configured to be able to supply the variable bias voltage to the bases of the second and third transistors. (4) In claim 2, the first to fourth circuits each include first and second transistors whose emitters are commonly connected and whose emitters are supplied with one of the two input signals. , third and fourth transistors whose emitters are commonly connected and to which the other of the two input signals is supplied; a load resistor which is commonly connected to the collectors of the second and fourth transistors; 2
and means for commonly supplying a constant bias voltage to the bases of the transistors @3, and to the collectors of the second and fourth transistors via the collectors of the first and third transistors and the load resistor. and means for supplying another constant bias voltage, and the first to fourth transistors are PNP transistors configured to be able to supply the variable bias voltage to the bases of the first or fourth transistors. A subcarrier phase adjustment circuit characterized by: