JPS63185295A - Burst signal generating device - Google Patents

Abstract

PURPOSE:To easily make circuits from the generation up to the phase adjust ment of a burst signal into a semiconductor integrated circuit by making a first subcarrier wave and a second subcarrier wave, the phase of which is 90 deg. delayed from that of the first subcarrier wave, be inputs, and outputting the output of the second adder only during a burst period with the aid of a modulator. CONSTITUTION:The phase of the burst signal 208 can be changed by a gain control signal 210, by adding the first subcarrier wave 201 and the signal 203 that the second subcarrier wave 202, the phase of which is 90 deg. delayed from the first subcarrier wave, is inverted, and adding the output signal 204 of the adder and the signal 206 that the output signal 204 of the adder is delayed and gain-controlled by the first gain control circuit 104. Accordingly, because the phase adjustment of the burst signal is performed by a direct current poten tial, they can be easily made into the semiconductor integrated circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION To Industrial Application Field 2/ The present invention relates to a burst signal generating device that is effective for use in a color television camera.

BACKGROUND OF THE INVENTION In recent years, as color television cameras have become more sophisticated and multifunctional, they must also be made smaller and lighter.

FIG. 3 shows a block diagram of a conventional burst phase adjustment device and color signal modulation circuit. The parts outside the broken line are not directly related to the present invention, so they will be briefly explained.

In FIG. 3, 1 is a first subcarrier, and 2 is a second subcarrier that is delayed in phase by 90 degrees from the first subcarrier 1. 13 is a first color signal, and 14 is a second color signal.

15 and 16 are gain control signals. 17 is a burst carrier. 18 is a phase-adjusted burst subcarrier. 19 is a signal in which a color signal and a burst subcarrier are mixed.

108 is a modulator, and 109 is a gain control circuit.

110 is an adder, 111 is a signal to burst phase shifter 3;
It is 7.

The operation of the conventional phase adjustment device configured as described above will be described below.

The burst phase shifter 111 is composed of an inductor, a capacitor, etc., and phase adjustment is performed by changing the constants of the inductor and capacitor.

Problems to be Solved by the Invention However, with the above configuration, it is difficult to integrate the circuit into a semiconductor integrated circuit, which hinders miniaturization and weight reduction.

The present invention has been made in view of the problems described in -F and provides a burst signal generating device that is easy to integrate.

Means for Solving the Problems In order to solve the above problems, the burst signal generation device of the present invention includes a first subcarrier and a second subcarrier whose phase is delayed by 90 degrees from the first subcarrier. an inverter that receives a carrier wave as input and inverts the first or second subcarrier; and a first adder that adds the subcarrier that is not input to the inverter and the subcarrier that has passed through the inverter. a delay device for delaying the output of the first adder; a first gain control circuit for gain controlling the output of the delay device; and a delay device for delaying the output of the first adder; The second adder adds the outputs of the gain control circuits, and the modulator outputs the output of the second adder only during the burst period.

Operation The present invention does not require the use of inductors or capacitors due to the above-described configuration, and since phase control can be performed using a DC potential, it can be integrated into a semiconductor integrated circuit together with a color signal modulation circuit.

Embodiment FIG. 1 shows a block diagram of a burst signal generator according to an embodiment of the present invention. In Figure 1, 1
01 is an inverter, and 102 is a first adder. 1
03 is a delay device, 104 is a first gain control circuit, and 105 is a second adder. 106 is a modulator.

The operation of the burst signal 5/signal generator of this embodiment constructed as described above will be explained below with reference to FIGS. 1 and 2.

First, FIG. 2 is a vector diagram showing the signal flow in this embodiment. In FIG. 1, 201 is the first subcarrier and 202 is the second subcarrier. The second subcarrier 202 is inverted by an inverter 101. The first subcarrier 201 and the output signal of the inverter 101 are:
They are added by the first adder 1o2. First adder 102
The output signal 204 is input to the delay device 103. The output signal 205 of the delay device 103 is transmitted to the first gain control circuit 104.
The gain is controlled by a gain control signal 210. The second adder 105 adds the output signal 204 of the first adder 102 and the output signal 206 of the first gain control circuit 104.

The output signal 207 of the second adder 105 is input to the modulator 106 and modulates the burst gate pulse 211. The output signal 208 of modulator 106 is a nost signal.

Even if the first subcarrier 201 becomes 2Q1' in FIG. 2, the output signal of the second adder reaches 207 in the same way. Therefore,
The phase of the output burst signal 208 is changed by the gain control signal 210, but the signals 207 and 20 in FIG.
The phase relationship between the two is always maintained at 90 degrees.

As described above, according to this embodiment, the first subcarrier 201
and a signal 203 obtained by inverting a second subcarrier 202 that is delayed in phase by 9Q degrees from the first subcarrier, and the output signal 204 of the adder and the output signal 204 of the adder are delayed. The phase of the burst signal 208 can be changed by the gain control signal 210 by adding the signal 206 whose gain has been controlled by the gain control circuit 104 of FIG.

Therefore, since the phase adjustment of the burst signal is performed using a DC potential, it is easy to integrate the burst signal into a semiconductor integrated circuit. Furthermore, according to this embodiment, even when the phase of the first subcarrier changes from 201 to 201 as shown in FIG. 2, the relative phase relationship of the burst signals at that time is maintained at 90 degrees. Therefore, it has the advantage that it can be used not only for the NTSC system but also for the PAL system.

Note that in this embodiment, the first subcarrier 201 and the second subcarrier 202 may be replaced.

As described in detail, according to the present invention, a circuit from burst signal generation to phase adjustment can be easily integrated into a semiconductor integrated circuit. However, it can also be used for NTSC and PAL video signals, with the same effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a burst signal generator according to an embodiment of the present invention, FIG. 2 is a signal vector diagram of the same embodiment, and FIG. 3 is a diagram of a conventional burst phase shifter and color signal modulation circuit. It is a block diagram. 101... Inverter, 102... First adder, 103... Delay device, 104... First gain control circuit, 105...・Second adder,
106...Modulator.

Claims (1)

[Claims] an inverter that receives a first subcarrier and a second subcarrier whose phase is delayed by 90 degrees from the first subcarrier and inverts the first or second subcarrier; and the inverter a first adder for adding a subcarrier that is not input to the inverter and a subcarrier that has passed through the inverter; a delay device for delaying the output of the first adder; and a delay device for delaying the output of the first adder; a first gain control circuit for gain control; a second adder for adding the output of the first adder and the output of the first gain control circuit; a modulator for outputting an output only during a burst period;
A burst signal generating device characterized in that a gain control circuit adjusts the phase of a burst signal.