A Bandwidth Expansion Method for Chrominance Signals with NTSC Receiver Compatibility

A bandwidth expansion method that is compatible with NTSC receivers is described. This method expands the transmissible bandwidth of the Q signal (the narrowband chrominance signal of the NTSC system) to 1.5 MHz by field-sequential transmission of high-frequency components of the I and Q signals. The compatibility of this method with NTSC receivers is satisfactory, and the method improves picture quality in some pictures by improving the color sharpness. Picture quality is further improved by compensating for the degraded frequency characteristics on vestigial sideband (VSB) transmission of the NTSC chrominance signals.