JPH04135023U - delay circuit - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose of the present invention is to realize a wideband delay circuit using a low-cost narrowband delay device and make it economically advantageous. [Configuration] Delay device 9-1, 9 with a frequency bandwidth of approximately 5 MHz
-2 are connected in parallel, the delayed input signals input to the respective delay devices are modulated with carrier signals having a phase difference of 180 degrees, and the respective output signals delayed by a predetermined amount are synthesized by the synthesizer 10. A delay circuit equivalent to a delay device for a carrier wave signal of twice the frequency is constructed.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to the improvement of delay circuits used in television cameras, monitors, etc. It is something.

0002

[Conventional technology]

In a delay circuit using a carrier signal, for example, a frequency bandwidth of 0 to 10 MHz When obtaining a signal, the frequency of the carrier signal and Therefore, it is necessary to use a signal of 20 MHz or more, which is twice the frequency bandwidth. NTSC system television equipment, the frequency is approximately 28.6 times the frequency of the subcarrier signal. MHz is commonly used. Conventionally, the frequency bandwidth is 0 to 10 MHz, and the carrier When configuring a delay circuit with a transmission frequency of 28.6MHz, use a glass delay line. However, the equipment was large and expensive, which was economically disadvantageous.

0003 FIG. 2 is a block diagram showing the configuration of a conventional delay circuit. 1 is the delayed signal input terminal Children 2, 4, 6, 8, 11, and 13 are buffers, and 3 is a low-pass filter (hereinafter LP F), 5 is the reference carrier wave input terminal, 15 is the doubler, 16 is the delay device, 14 is the delayed This is a signal output terminal. Next, this operation is applied to an NTSC television signal (Japanese Implemented as a 1H (63.5 μsec) delay circuit for standard color television system Let's explain the case. NTSC television is connected to delayed signal input terminal 1. input a television signal (hereinafter abbreviated as television signal) and pass it through buffer 2 to LPF 3. Connect to.

0004 Based on the modulation theorem, the LPF 3 has a frequency of 1/2 of the carrier signal frequency of the delay device 16, which will be described later. This is the frequency bandwidth, and this output is connected to the delayed signal input terminal of the delay device 16. . Next, the reference carrier signal input to the reference carrier input terminal 5, generally in the NTSC format. 4 times the frequency of the subcarrier signal of the color television signal, that is, 3.579 Approximately 14.3 MHz, which is four times 545 Hz, is used. This reference carrier signal The frequency becomes 28.6MHz through the doubler 15 through the buffer 6, and is delayed through the buffer 8. It is connected to the carrier wave input terminal of the device 16. The delay device 16 is connected to the delayed signal input terminal. The input delayed signal is modulated by the carrier wave signal input to the carrier wave input terminal, and The delayed signal is outputted to the buffer 11.

[0005] The reason why a 28.6 MHz signal is used as the carrier wave signal of the delay device 16 is because the television This is to ensure a frequency bandwidth of 0 to about 10 MHz for the John signal. Next, the signal passed through the buffer 11 is sent to the LPF 12, which removes the carrier wave component of the delayed signal. The signal is then output to the delayed signal output terminal 14 through the buffer 13. As explained above, the television signal input to the delayed signal input terminal 1 is The signal is delayed (for example, by 1H) and is output to the delayed signal output terminal 14.

[0006]

[Problem that the idea aims to solve]

Conventionally, a circuit using a glass delay line as the delay device 16 is common, but the frequency Since the bandwidth is wide from 0 to about 10 MHz, the glass delay line is expensive and economical. It has the disadvantage of being at a disadvantage. In addition, the frequency is 28.6MHz, which is a high frequency signal for television signals. It also has the disadvantage of requiring advanced techniques such as noise processing. The present invention eliminates these drawbacks. low-cost CCD delay elements or glass delay elements with a frequency bandwidth of 0 to about 5 MHz. A delay circuit with a frequency bandwidth of 0 to approximately 10 MHz can be realized by extending the line, making it economically advantageous. The purpose is to

[0007]

[Means to solve the problem]

In order to achieve the above-mentioned purpose, the present invention has a frequency bandwidth of, for example, 0 to about 5 MHz. Two low-cost delay devices such as CCD delay elements or glass delay lines are connected in parallel, and this Using carrier signals with a 180° phase difference as modulation carrier signals, these two delay devices By combining the output signals, the frequency bandwidth (0 to 1 This constitutes a delay circuit (0MHz).

[0008]

[Effect]

As a result, for example, if two delay devices are connected in parallel, one delay device has 0° and the other By using carrier signals with a 180° phase difference in one delay device, it is possible to effectively A delay circuit using a carrier wave signal of twice the frequency is constructed. Therefore, by using a delay device with a frequency bandwidth of, for example, 0 to 5 MHz, A delay circuit with a frequency bandwidth of 0 to 10 MHz can be realized.

[0009]

【Example】

FIG. 1 is a block diagram showing the configuration of a delay circuit according to an embodiment of the present invention. 1 is an input terminal for the delayed signal, 2, 4, 6, 8, 11, 13 are buffers, 3, 12 is an LPF, 5 is a reference carrier wave input terminal, 7 is a phase shifter, 9-1 and 9-2 are delay devices, 1 0 is a synthesizer, and 14 is a delayed signal output terminal. Next, we will convert this operation to the NTSC system. When implemented as a 1H (63.5μsec) delay circuit for a television signal of explain about.

0010 Input a television signal to delayed signal input terminal 1, pass through buffer 2 to LP Supply to F3. Here, the LPF 3 is defined by delay devices 9-1 and 9, which will be described later, based on the modulation theorem. -2 carrier wave signal, and this output is the delay device 9-1, 9 -2 is supplied to the input terminal of the delayed signal. Next, input it to the reference signal input terminal 5. reference carrier signal, typically a subcarrier of an NTSC color television signal Approximately 14.3MHz, which is four times the frequency of the signal, that is, four times 3.579545MHz. z is used. This reference carrier signal is transmitted through the buffer 6 to the delay device 9-2. The signal is supplied to the wave input terminal and the phase shifter 7. The phase shifter 7 sets the reference carrier signal in 180° phase. This signal is supplied to the carrier wave input terminal of delay device 9-1 through buffer 8. be done.

[0011] Here, the carrier signals of delay devices 9-1 and 9-2 have the same frequency and a phase of 180°. It's a different signal. Delay devices 9-1 and 9-2 have the same electrical characteristics, and each The delayed signal input to each delayed signal input terminal is input to each carrier wave input terminal. A synthesizer modulates the input carrier wave signal and synthesizes two delayed signals with a specified delay. Synthesize in 10. Here, the output signal of this synthesizer 10 is Since the phases of the carrier wave signals differ by 180°, the frequency of the carrier wave signal The frequency is the same as that modulated at 28.6 MHz. And the bag The carrier wave component of the delayed signal is removed by the LPF 12 through the filter 11. The output signal is outputted to the delayed signal output terminal 14 through the buffer 13.

0012

[Effect of the idea]

As explained above, according to the present invention, the frequency bandwidth of a single delay element is 0 to 5M. Hz, it is possible to implement a delay circuit with twice the frequency bandwidth of 0 to 10 MHz with a simple configuration. can be expressed. In addition, the frequency bandwidth of a single delay element is 5M compared to a delay element of 10MHz. Since the cost of a Hz delay element is about 1/10th of the price, it is economically advantageous. The delay circuit of this invention is used in comb filters for television monitors and television cameras. It can be used in vertical contour correction circuits for cameras and monitors.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional configuration.

[Explanation of symbols]

1 Delayed signal input terminal 5 Carrier signal input terminal 7 Phaser 9-1, 9-2 Delay device 10 Synthesizer 14 Delayed signal output terminal

Claims (1)

[Scope of utility model registration request] [Claim 1] In a delay circuit using a carrier wave signal,
A delayed device has a configuration in which multiple delay devices with the same electrical characteristics are connected in parallel, carrier signals with different phases are supplied to each of the multiple delay devices, and the output signals of the multiple delay devices are combined. A delay circuit characterized by widening the frequency band of a signal.