JPS63193789A - Camera built-in vtr - Google Patents

Abstract

PURPOSE:To enlarge a dynamic range by setting an encoder output level less than twice a peak-to-peak (VP-P), and setting the dividing ratio of a dividing device between an encoder and an interface of a camera part and a video part larger than 1/2. CONSTITUTION:Respective signal processing circuits 51-53 drop the levels of a luminance signal Y, and chrominance components (R-Y) and (B-Y) so that the input level of the encoder IC54 in a next stage becomes K-fold (0<K<1). Consequently, the input level of the luminance signal Y for the encoder IC54 becomes smaller than a rated value K Vino (rated input level, 0<K<1), and the output level of the output terminal 18 of the encoder IC54 goes to K Vouto (rated output level, 0<K<1, normally 2 VP-P). The dividing ratio is selected as 1/2K in the dividing device 55, whereby a rated value 1 VP-P can be obtained as a signal level for the video part. Thus, the luminance signal level of the encoder IC54 goes to 1/K, whereby the dynamic range relatively goes to K-fold.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a signal processing device for a camera-integrated VTFL,
In particular, the present invention relates to a device suitable for an encoder IC.

[Conventional technology]

In conventional camera-integrated VTRs, the encoder IC is shared with that of the stand-alone video camera, and its input and output levels are used at their rated values.

The output was divided in half and output to the video section. An example of an encoder IC with a power supply voltage of 5V is "Hitachi Consumer's IC Data Book (VTR IC), P1.
There is HA 11776 AMP of 20 to P 124 J. The specifications of this IC's positive output D B of the Y amplifier are 102% to 135%, and when used at a rated value of 1 woodworking Ct, the maximum output level can only be 102% due to variations.

[Problem that the invention seeks to solve]

In the conventional technology described above, the output level of the encoder IC is rated at 2VP-P, which is 2.4 including the white peak.
A dynamic range of about Vp-p (peak-to-peak) is required, but with the recent encoder 1C whose power supply voltage is around 5V aimed at low power consumption, it is not possible to have a dynamic range with sufficient margin. Lower the white peak value to about 110%. Compromises the gluing quality on the white peak side.

There was a problem in having to either tolerate variations in the maximum amplitude level.

An object of the present invention is to relatively expand the dynamic range by lowering the input/output level of the luminance signal of the encoder IC below the rated value.

[Means for solving problems]

In a camera-integrated VTR, the output from the camera section is not sent directly to the TV, so the signal level is 1 VP at the sending end impedance of 75 ohms and the terminating impedance of 75 ohms.
−, there is no need to protect. Further, since the signal processing of the luminance signal in the encoder IC used is only a fade function and addition with the color signal, there is no problem even if it is used at less than the rated value.

Therefore, the above purpose is to set the encoder output level to 2 v
This is achieved by making the splitting ratio of the splitting device between the encoder and the interface of the camera part and the video part less than 1/2 as less than pp.

[Effect]

According to the above, even if some encoder ICs have a narrow dynamic range of video signals due to manufacturing variations, a large dynamic range can always be obtained.

〔Example〕

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

Figure 1 shows an example in which the connection between the camera section and the video section is NTSC.
This is done using a signal.

In FIG. 1, a luminance signal Y1 and a color difference signal RY.

B-Y are individual signal processing circuits 51, 52, 55, respectively.
The input level of the next stage encoder TC54 is doubled (
The level is lowered so that 0<K<1). Therefore, the input level of the luminance signal Y from the button to the encoder IC54 becomes less than the rated value KVino (Vino is the rated input level, o<K<1), and the output level of the output terminal 18 of the encoder IC54 is KvOtLto (VOtLtO
C Rated output level, 0<K<1. Usually 2 Vp-p
). Here, the encoder IC54 is Hitachi's HA 11776AMP, which performs fade function, blanking, and 5YNC addition for the luminance signal Y, and peak clip and balance modulation for the color signals (L-Y and 13-Y).・It performs signal processing such as blanking and burst addition, and outputs an NTSC signal to the 18th terminal. This output is input to the level dividing device 55 at the next stage.

In the dividing device 55, the dividing ratio is selected to be 1/2K, which means that the rated value of 1Vp-P can be obtained from K as the signal level to the video section. This results in
Since the luminance signal level of the encoder IC 54 is reduced to 1/2, the relative EFJIC dynamic range is doubled.

Figure 2 shows how the camera section and video section are connected to NTSC signals and CHR.
This is a circuit configuration that performs OMA multiplied signals, and FIG. 3 shows a circuit configuration that operates a camera section and a video section using Y+5YNC signals and CHROMA signals.

〔Effect of the invention〕

According to the present invention, even if an encoder IC with a power supply voltage of around 5V is used, a wide dynamic range can be provided, so there is a potential for improved performance such as improved linearity and reduced variation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a block diagram of another embodiment, and FIG. 3 is a block diagram of another embodiment. 1...Input terminal for luminance signal. 2.3... input terminal for color difference signal, 4... encoder IC. 5... NTSC signal of encoder output 6... Division device. 7...Camera output NTSC signal. 8... Color signal output. 9...Y+5YNC signal of encoder output. 10...Y+5YNC signal of camera output.

Claims (1)

[Claims] 1. When a video camera and a VTR are integrated, the output of the encoder IC of the camera section is passed through a level division device to the output of the camera section, and the signal level of the output of the camera section is set to 1V_p_-
Camera-integrated VT with _p (peak-to-peak)
In R, the input level of the encoder IC is multiplied by K times (
However, by setting 0<K<1), the output level is also multiplied by K, and the division ratio of the level division device by the division device is set to 1/2K.
T.R.