Browse Prior Art Database

DISCRIMINATION of NTSC and PAL SCHEMES

IP.com Disclosure Number: IPCOM000040218D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 89K

Publishing Venue

IBM

Related People

Mizukoshi, Y: AUTHOR

Abstract

This article describes a discrimination technique for choosing between a NTSC (National Television System Committee) scheme and a PAL (Phase Alternation Line) scheme under which a television receiver is operated. The discrimination is made during a field blanking period of a composite video signal. Operational timing of an image scanning device coupled to the television receiver is selected to adapt with the NTSC or PAL scheme of the television receiver. An image scanning device, such as a video camera, is connected to a television receiver which is operated in the NTSC scheme or the PAL scheme through an adapter unit. It is necessary to adapt the operational timing of the image scanning device to the NTSC scheme or the PAL scheme. Fig. 1 shows composite video signals A and E in the NTSC scheme, and Fig.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

DISCRIMINATION of NTSC and PAL SCHEMES

This article describes a discrimination technique for choosing between a NTSC (National Television System Committee) scheme and a PAL (Phase Alternation Line) scheme under which a television receiver is operated. The discrimination is made during a field blanking period of a composite video signal. Operational timing of an image scanning device coupled to the television receiver is selected to adapt with the NTSC or PAL scheme of the television receiver. An image scanning device, such as a video camera, is connected to a television receiver which is operated in the NTSC scheme or the PAL scheme through an adapter unit. It is necessary to adapt the operational timing of the image scanning device to the NTSC scheme or the PAL scheme. Fig. 1 shows composite video signals A and E in the NTSC scheme, and Fig. 2 shows composite video signals I and M in the PAL scheme.

(Image Omitted)

Fig. 3 shows a synchronization separating circuit included in the adapter unit. The composite video signal in the television receiver is applied to a synchronization (SYNC) clamp circuit 1. The output of the SYNC clamp circuit 1 is applied to a high-pass filter 2 and a low-pass filter 3. Both output signals of filters 2 and 3 are applied to pulse shapers 4 and 5, respectively. Pulse shaper 4 generates horizontal synchronization (H SYNC) pulses (not shown) which are separated by half of the horizontal synchronization period, i.e., H/2. Pulse shaper 5 generates vertical synchronization (V SYNC) pulse B, F, J or N, which have a small delay generated in Schmitt trigger inverters in the pulse shaper. Th...