Commercial Analog to Digital electronics (ADCs and TDCs) for physics applications have historically been developed for use in both CAMAC and FASTBUS crate systems. These systems provide a flexible, modular design that supports high power and low noise for the analog side, and a fast parallel backplane for efficent readout of the digitized data. However, in recent years the number of companies that are providing electronics in these form factors is declining. More importantly, the development of new hardware and technology designs for these form-factors is dwindling.
In the past 10 years the physics community has slowly embraced a different modular electronics bus standard (VME) for many applications. The VME standard has many advantages that include a faster bus speed (up to 160 MBytes/s), but perhaps more importantly it has broad support in many other commercial industries. This should make hardware and electronics using the VME standard viable and affordable in the marketplace for many years to come.
The VME standard does suffer from some deficiences with respect to Physics specific applications. These include a lack of a standard for high-power, low noise voltage supplies to support analog electronics. For readout, there has been no standard for slave-terminated or multi-module block transfers. For several years some vendors (CAEN) have supported a CERN specified extension to VME called V430. It provides for additional voltages and more power to VME modules via a third (P0) connector. More recently, the VME International Trade Association (VITA) has adopted a new standard for VME in Physics Applications (VIPA) which addresses all of the issues. Early adopters of the new VIPA standard include several experiments at Fermilab.