They are both experimental engines designed for speeds faster than sound, or hypersonic. Both are jet engines with no moving parts which rely on the huge pressures produced by supersonic airflow into an engine to ignite the fuel. This removes the requirement of turbines and compressors used in turbofan engines found on most conventional jet planes. A Ramjet’s combustion chamber, where the fuel is mixed with air and ignited, works only at subsonic speeds. As the intake slows the air down it releases some of the energy as a shock wave, unfortunately this reduces fuel efficiency. The Scramjet built on this design and has a combustion chamber that is designed specially to operate with supersonic airflow. The name Scramjet is an acronym for ‘supersonic combustion’ ramjet. Scramjet technology has been under development since the 1950s, but not until recently have scramjets successfully achieved powered flight and still only in experimental projects.
In a word – Yes
The main difference is that a ramjet will slow incoming air to subsonic speeds as part of the compression and combustion cycle. A scramjet keeps the incoming air at supersonic speeds.