| 摘要 |
The digital data to be converted is output from a store as a stream of four-bit words two digital analog converters, a pair of bits at a time. Two four-level analog signals are output to filters where their bandwidths are limited to 1.7MHZ. A mixer modulates a four level signal onto a 3.58 MHZ subcarrier signal from an oscillator. The modulated signal, four level analog signal and video syn signals on a line are summed to provide a composite signal. The component from zero to 1.7 MHZ is the first four-level signal, and the component between 1.9 and 5.3 MHZ is the modulated subcarrier. The composite signal is recored on a video disc using a frequency modulator and an intensity modulator. |
