Key technical activities include the following developmental efforts:
Direct tape system calibrator including 10Hz - 10 MHz low distortion sinewave oscillator, digital frequency meter, wideband digital AC voltmeter, automatic leveling and tracking harmonic distortion analyzer, and precision (.005%) DC reference.
Flutter meter for IRIG instrumentation tape recorders. Analyzer measures tape flutter, time base error, and dynamic skew. Special features include IEEE488 and RS-232 interfaces and intelligent meter damping to minimize delays in reading.
Calaway & Brooks has built and shipped more than 1000 of the tape system calibrators and flutter meters and provides ongoing maintenance and calibration services.
Transient waveform recorder. Operating in conjunction with an IBM PC, the SDA2000 will digitize up to eight channels at rates up to 10 Megasamples/sec, and has storage of 2 Megasamples of data. The PC offers control menus, waveform calculations, and graphic display of both recorded and calculated data.
Environmental control system for Beech Starship twin propjet. System controls flow of engine bleed air for cabin pressurization and heating, provides proportional temperature control, and apportions air flow to cabin and cockpit. Dual NSC800 microprocessors provide fail-safe redundant operation. We manufactured over 200 of the controllers, and, for many years, supported them with periodic overhauls, upgrades, and repairs.
Transcutaneous Electrical Neural Stimulator (TENS) used in the control of chronic pain. Calaway & Brooks developed the electronic circuit, participated in packaging and injection mold design, and manufactured about 8,000 units. This product was eventually sold to Medtronic, Inc.
Observer-based digital servos for optical disk (CD) mastering station:
The system uses an Analog Devices ADSP2101 DSP chip to implement four servos simultaneously. Each of the controlled axes has a bandwidth of 1000 Hz and phase margin of 45 degrees.
Spindle servo for magnetic disk test/development system:
The spindle is phase-locked to a synthesized reference clock and is fully programmable for speeds from 300 to 12,000 RPM. Acceleration and deceleration ramps are under velocity control.
Digital capstan servo for very low speed arcuate-scan computer backup tape drive:
80C196KR based servo applies quadricorrelator techniques to an incremental encoder to achieve wide bandwidth (>100 Hz) at arbitrarily low tape speed. This demonstration system is currently being adapted for a commercial product.
Digital servo for reaction wheel used in attitude control of a low earth orbit communica-tions satellite:
An ADSP2101 controls wheel speed and acceleration and implements control communications.
Circuit design and component selection consulting, printed circuit design, EMI testing (CE Mark qualification) for a line of mass flow controllers used for precise control of gasses used in semiconductor processing equipment.
Development of barometric calculator used to compute parachute release settings based on landing zone elevation. Calculator measures landing zone barometric pressure, calculates equivalent MSL elevation, and computes release setting for a given above-ground altitude. Calaway & Brooks designed, packaged, and assembled these calculators.
Development of a Time-Division Multiplexer to enable recording of up to eight channels of data on a single channel, 8MHz recorder. The TDM-8E makes extensive use of 30MHz clock rate FIR digital filters for anti-aliasing and dual port memory for time-compression and expansion. All functions, including channel gains and offsets, are remotely settable via IEEE-488 and serial ports and also by a Windows-based virtual front panel.
Upgrade of cockpit annunciators used in commercial cargo aircraft. The redesigned assemblies replace the original relays and incandescent lamps with electronically dimmed LED lamps for significant savings in power, weight, and reliability.