7904
The 7904 is a 500 MHz mainframe with four bays. It accepts two 7000-series vertical plug-ins and two 7000-series horizontal plug-ins. It was introduced in late 1971/early 1972 (Note 1). The successor model 7904A was introduced in 1974.
Performance is largely determined by the plug-ins. The 7904 makes extensive use of custom integrated circuits and hybrid circuits. The signal path is completely differential and all of the internal wiring is 50 Ω coax.
The 7904 has a many modes of operation. One mode is called "Independent-Pairs Display" in the manual, where the input to the left vertical plug-in is displayed using the B horizontal timebase plug-in, and the input to the right vertical plug-in is displayed using the A horizontal timebase plug-in. This resembles the trace-slaving "ALT" mode that is produced by an 1A4 in a 547. Many other modes are available. It is possible to put vertical plug-ins in the horizontal slots for X-Y operation. It is even possible to put a horizontal plug-in in one of the vertical slots to produce a raster scan. The CRT has distributed vertical deflection plates.
Specifications
Key Specifications
| Bandwidth | 500 MHz |
|---|---|
| Fastest calibrated sweep | 500 ps/Div (with 7B92A) |
| Acceleration voltage | 24 kV |
Links
Notes
- See 7A11 and John Addis, Good Engineering and Fast Vertical Amplifiers, in Jim Williams (Ed.), Analog Circuit Design: Art, Science and Personalities (1991), p.114.
Pictures
-
7904 w Plugin
-
7904A
-
Plug-in interface board front
-
Plug-in interface board rear
-
7904 block diagram
