[old_tv_nut]

Regarding recording progressive scan on the HDD-1000, Zenith didn't modify their HDD-1000, but used the "Format Converter" devised by Charlie Rhodes (formerly Tektronix, and head of the Advanced Television Testing Center at the time). This device segmented each frame into rectangular pieces and fit the pieces into the Sony image format for recording, and then reassembled the progressive frame on playback.

This device was used for all the test material in all proposed formats at the ATTC so they could use unmodified Sony tape equipment.

The Sony tape heads were very sensitive to contamination and wear, and we were constantly monitoring the signal quality, having to replace the heads several times over the years of testing. Later, in the 2000's, when we were in new facilities, smoke from some burned food in the kitchen appliance division got into the ventilation system. It was just a nuisance smell for our employees, but it clogged the Sony heads, which had to be replaced.

Before the HD tape machines arrived, Zenith's work on HD used a frame store that could hold 10 seconds of HD material. The semiconductor memories at the time required a 6-foot tall rack to hold enough chips for 10 seconds of video, and cost several hundred thousand dollars in itself.