Commercial Products Developed (excluding integrated circuits developed)
CTI/Siemens 951, 921 (EXACT), and 961 (EXACT HR) PET Medical Imaging Tomographs--front-end electronics
Circuits derive event energy, position, and time from 8 x 8 BGO block scintillation detectors.)
- Discrete circuits and later circuits using custom CMOS chips located in the majority of PET tomographs around the world (over 200 as of December 1999).
- Detector channels include four-channel, wideband (25 MHz) variable gain amplifiers with gated baseline restorer autozero circuits for amplifying scintillation detector current pulses.
- Detector channels include two position (X and Y) and one energy (E) gated integrator with flash A/D converter on energy signal and ratiometric flash A/D converters (ladder driven by energy signal) on position signals.
- Detector channels include constant fraction discriminator (CFD) time derivation circuits with subnanosecond time dispersion (walk) for variable amplitude signals.
- Circuits include high-speed operational transconductance amplifiers (OTAs), current and voltage feedback op amps, ECL output voltage comparators, ECL logic, and support components.
CTI 711 Time-of-Flight PET Medical Imaging Tomograph--front-end electronics
(Circuits derive event energy and time from discrete BaF2 scintillation detectors.)
- Constant fraction time derivation circuit with subnanosecond time dispersion for varying amplitude signals; extensive microstrip ECL logic.
- 62.5 ps resolution time-to-digital converter for localizing event by difference in detected event flight time.
- Time-to-digital converter includes wideband feedback amplifier and subnanosecond bipolar transistor current-mode switches with beta compensation.
CTI/Siemens PET, SPECT Medical Imaging Patient Beds--all electronics
(Circuits provide microprocessor control of horizontal and vertical motions.)
- High voltage, power MOSFET H-drivers (90 Vdc at 3 A) for controlling dc motors.
- Microprocessor interface circuits for monitoring and controlling motions; robust EMI/RFI and surge protection applied to all external signals.
- Redundant circuits used to ensure patient safety.
CTI 82Rb Medical Patient Infusion System--all electronics and firmware
(Circuits provide microprocessor controlled, assayed dose of radionuclide for patient imaging.)
- High voltage (1,000 Vdc) detector components, pulse comparators, and ECL logic.
- User control and display panel; microprocessor and interface circuits; programmable, registered logic devices for state machine design.
- Complex microprocessor control and measurement firmware written in assembly language and C.
- System includes fundamental limitations on patient dose and pressure for patient safety.
TEC 600 Nuclear Power Plant Radiation Monitoring System--major electronics
(Circuits process and digitally communicate remote site radiation and other measurements.)
- Widerange (10 pA to 1000 μA) electrometers with A/D converters.
- Multichannel A/D and D/A circuits for analog data acquisition and control.
- Transformer and optically isolated RS422 digital biphase drivers for system loop communications with automatic data bypass for power and watchdog timer failures.
- Full duplex, synchronous HDLC/SDLC multichannel loop, and asynchronous single-channel RS-232/422/423, 20 mA current loop, and TTL communications circuits.
- Full VME digital asynchronous buss interface.
TEC 1414 Nuclear Power Plant Relief Valve Monitoring System--all electronics
(Circuits process acoustic accelerometer signals and determine if relief valve is open.)
- System required after 3-mile island nuclear mishap; system in the majority of U.S. nuclear power plant containment buildings.
- Radiation hardened (200 Mrad) accelerometer charge-sensitive preamplifier powered by dc current superimposed on single-wire output.
- Amplification, filtering, rms-to-dc conversion, display, and decision circuits.
TEC 1430 Nuclear Power Plant Loose Parts Monitoring System--major electronics
(Circuits separate and detect the acoustic signature of loose parts out of operating acoustic background.)
- Differential input, instrumentation amplifiers with selectable gain and bandpass filtering.
- Elliptic lowpass filtering (notch at accelerometer resonance) followed by RMS-to-DC converter for envelope detection.
- Envelope signal processing with adaptive threshold to separate impact events from background noise.
- Built-in self test circuits.
- Superheterodyne downconverter to convert ultrasonic acoustic signals to the audible range.
TEC 1302 Acoustic Emission Instrument--all electronics and mechanical design
(Circuits process, discriminate, and display ultrasonic acoustic emission for mechanical cracks, leaks, weld integrity, and rotating machinery diagnostics.)
- Multipole bandpass filtering (100 - 500 kHz) with selectable frequency notch; filters followed by selectable gain and rms-to-dc conversion.
- Selectable threshold zero-crossing comparator for counting crossing of CW or envelope signal.
- Analog-to-digital conversion using voltage-to-frequency converter and counters.
- Selectable digital display for rms signal level, counts, or count rate of either CW or envelope signal.
TEC 156 and 981 Nuclear Power Plant Signal Isolation Systems--all electronics
(Circuits provide electrically isolated monitoring of critical analog and digital signals.)
- 2,000 V input isolation with 120 dB, 60 Hz rejection for analog inputs; analog inputs either voltage or current; analog outputs are 4 - 20 mA currents.
- 1,000 V isolation for digital inputs; digital inputs either voltage or resistance; open-drain (power MOSFET) digital outputs.
Spectron Development Laboratories 1522 Laser Interferometry Doppler Processor--PLL frequency synthesizers and RF front ends
(Circuits used for measurement of partical size and velocity from optical signature detected in photomultiplier tube.)
- 15- and 22.5 MHz PLL frequency synthesizers; both fixed frequency and 10 kHz channel units developed.
- Low noise (< 3 dB noise figure) 15- and 22.5 MHz tuned RF front-end amplifiers.
- Period measuring circuits (TTL logic) for measuring and calibrating doppler frequency shift.
- High voltage (150 Vdc at 5 A) laser power supply.