I was watching an old TNT ufo documentary about a UFO sighting that happened on July 17, 1957. It was tracked all over the country by ground and air based radars. Civilian and Air Force. An airliner had to take evasive maneuvers to avoid hitting it causing injuries to ten passengers. It started on the West coast and flew across New Mexico to Mississippi then back to Texas and then continued north through Oklahoma and Kansas. The persuit was ended when the jets had to land for fuel. Now the UFO was identified with an ALA-5 pulse analyzer as having a

Pulse of 3,000 mega cycle envelope
Duration of 2 micro seconds
Repitition Frequency of 600 cycles/second

Can anyone elaborate on what this means and what sort of craft would have caused this in 1957?