Definitions:                                                                   [Test Point Nominal Values]   [Site graphic Library]

(U)CERD -   Universal Combined Exciter Reciever Digital analog board. The Exciter is responsible for producing the "RF Drive" signal for the RF Amplifier. The drive signal Gain is controlled in this module by the Transmit Gain (TG) value. 

Combiner-    The Hybrid Splitter is used to split the transmit RF section to drive the RF Coil from two points for better Signal to Noise. On Receive, this splitter acts as a signal combiner which combines the two signals from the two separate points and delivers  a single high quality, Low noise signal back to the Receiver for processing.

PSD Sequence- Pulse Sequence Database. PSD's are made up of a combination of wave shapes that will drive the RF and Gradient subsystem to produce a desired result. They also contain all the system configuration parameters to achieve a certain image. Some of the most common PSD's are: SE (Spin-Echo), IR (Inversion Recovery), FSE (Fast Spin-Echo.)

Directional Coupler- Also referred to as "QDC" or Quad directional Coupler, or "Coupler". The term "quad" refers to the 4 basic modes of coil configurations the RF system has been to designed for. Head, Body, Surface, Multi-coil. Its purpose is:

  1. To provide a sampling point for the system Power Monitor
  2.  In some older Signa systems, it provides a sample for the RF Envelope Feedback system.
  3.  It is also used as a point to introduce a +15vdc reference voltage to drive the T/R Biasing of the Transmit/Receive mode circuitry.

Dummy Load- A device that is used to absorb high RF energy. Usually used to take the place of a normal load at the output of an amplifier. They can be oil filled to dissipate heat or air cooled.

Attenuator- A device that is designed to reduce the output of an amplifier to a particular sample size. They are generally rated in Decibels (dB) and come in many different forms.

Note: GE uses a 200 Watt, 30dB Dummy Load, Attenuator in the RF Power Measurement kit (46-317724G1 or G2)  Bird Model: 8322 or equivalent. 

Power Formulas-  These formulas may be useful. excel [Voltage to Watts Calculator]

 Convert Voltage level to Watts.

Decibel to Decibel per Meter

Cables and Connectors- Many of the cables and connectors found on the RF system are rated at different power ratings. See part numbers below:.

Multi-coil & Surface Coil- [Under Construction]