Includes all aspects of digital and analogue filters and filter networks, also frequency selective networks.

Digital filters including details of: filter type e.g. recursive, adaptive, filter function e.g. low-pass, band-pass, notch filter, comb filters etc. and filter construction and operation e.g. components and configuration. Time delay and time varying (including adaptive) networks e.g. N-path filters. Frequency selective network details e.g. active and passive networks, and function and operational details e.g. low-pass, band-pass and high-pass filter networks.

Impedance converters. Signal splitting/combining, impedance matching, balanced-to-unbalanced networks. Tone or bandwidth control, phase shift networks etc. Continuous tuning and discontinuous tuning; band selection arrangements e.g. band-switching. Automatic band scanning; automatic frequency control. Waveguide technology filters and impedance networks with distributed constant elements are covered by the Derwent ITP 'Radio Frequency Waveguides and Distributed-Constant Components'.
ISSN 1463-7979

Includes semiconductor and valve amplifier circuit details and applications e.g. instrumentation, high and low frequency, power, audio and logarithmic amplification arrangements. Circuit type and configuration details including; differential and operational amplifiers, current mirror, emitter follower circuit, switched capacitor, phase splitter circuits, DC coupled, chopper modulation, cascade, cascode, bridge and gated amplifiers etc.

Arrangements for modifying amplifier performance e.g. negative feedback, over-current or over-voltage protection, noise reduction, offset reduction, bandwidth extension, arrangements for improving stability, efficiency, CMRR and gain etc. Includes details of technology used for amplifier implementation e.g. discrete and integrated bipolar and FET devices, amplifier modules using operational amplifiers, valve, parametric and microwave/millimetre wave amplifier details.

Gain control details; compression and expansion, AGC, muting and general signal rectifiers. Details specific to audio amplifiers includes tone and volume control; balancing. General amplifier construction details and testing arrangements.
ISSN 1463-7995

This profile includes the application of test equipment, circuits and methods to testing for specific electrical properties, and locating electrical faults in particular types of electrical and electronic components, circuits and equipment.
ISSN: 1467-3096

Includes coding, decoding and code conversion arrangements, e.g. types of D/A, A/D conversion elements, e.g. Flash A/D converters, delta and differential modulation, and code conversion e.g. static code converters, parallel/series and series/parallel conversion, series transmission code, Manchester, biphase level coding and coding associated with computer keyboards or printers. Error detection and correction e.g. parity. Data conversion in computing applications.

See Derwent ITP 'Coding Systems for Information Transmission' for details of coding schemes and equipment used in communications.
ISSN 1463-7944

Includes circuits for the generation and manipulation of electronic pulses. Coverage includes pulse counters and frequency dividers characterised by type and counter details e.g. synchronous and asynchronous counter details, divide-by-N counters etc. Counters characterised by random or specific code output e.g. using Gray code, and type of device used e.g. semiconductor devices.

Arrangements for generating electric pulses, generating finite slope or stepped portion pulses, and pulse manipulation details e.g. shaping, comparing and sorting pulses, monitoring pulses, changing timing of pulses at single output and changing pulse train pattern e.g. using frequency dividers/multipliers etc. Pulse distribution circuits e.g. clock signal distributors, arrangements for delivering pulses as a function of the input signal, e.g. comparator generating pulse output in response to input, individual pulse peak detector.

Phase/frequency control and synchronisation. Pulse modulation and demodulation arrangements e.g. PWM, PPM, PAM PFM etc.
ISSN 1463-7960

General electronic switching or gating arrangements using non-mechanical devices e.g. characterised by electronic switching device; FETs, thyristors, triacs, optoelectronic devices etc. Circuit details; controlling switching point, proximity and touch switches, accelerating switching speed, reducing power consumption, switch protection, compensation for variations of physical values e.g. temperature etc. Sample and hold arrangements, and applications of electronic switching circuits e.g. power converters and power switching, logic and signal switching and computer applications.

Switches and relays for power applications are included in the Derwent ITP 'Electromechanical Switches' . Switching for circuit protection is covered by the ITP 'Electrical Switchgear and Circuit Protection'.
ISSN 1463-7952

Thin and thick film devices and packaging, e.g. thin film two-dimensional arrays e.g. for memories, LCDs, ELDs etc, and thin film transducers, and thick film devices. Coverage includes details of hybrid circuits e.g. high frequency ICs including MMICs, and hybrid circuit packages and terminals.

IC chip mountings onto hybrid and details of materials and structures for multilayer ceramic wiring board. Hybrid and thick film circuit manufacture details. Superconductive thin/thick film devices and circuits.
ISSN 1463-791X

Semiconductor integrated circuit devices characterised by type e.g. programmable logic devices, semiconductor memory e.g. RAM, EEPROM, customised IC arrays etc. Charge transfer devices, IC radiation sensors and detectors including solid state imager details e.g. charge coupled devices.

Includes analogue and digital circuits and details of integrated circuit structures based on technology e.g. with bipolar devices, FETs and combined FET and bipolar devices i.e. BiCMOS, BiFET structures etc.

Covers mountings for unpackaged IC chips onto substrate, encapsulation details for individual chips and interconnections between several chips on a substrate. Includes details of discrete devices intended to be used as elements of an IC, e.g. a floating gate transistor for an EEPROM.
ISSN 1463-7901

Includes logic circuits characterised by components e.g. bipolar transistors and diodes; ECL, TTL , integrated injection logic, and FETs; MESFET, MOSFET, dynamic MOSFET and combined FET and bipolar devices. Logic blocks implemented with circuit blocks e.g. using operational amplifiers, multiplexers etc. programmable logic devices and logic circuits using optoelectronic devices.

Covers interface circuits e.g. inter-family interfacing arrangements e.g. TTL-CMOS, and drive circuits for displays etc. Logic function and general integrated circuit details, e.g. input-output details, power supply and noise prevention, inverters and details of logic gates and novel circuits which perform logic functions i.e. arithmetic (AND, OR etc.) and fuzzy logic circuits. Computer-aided logic design systems e.g. simulators, logic circuit CAD etc.
ISSN 1463-7936

Covers circuits dealing with sinusoidal oscillations, and digital implementations of circuits e.g. phase locked loops, phase detectors etc. which may be interfaced with analogue systems. Includes sinusoidal oscillators e.g. amplifier with regenerative feedback, frequency multipliers/dividers, phase or frequency comparators and automatic phase/frequency control and synchronisation including PLL; VCO, phase and lock detector, frequency synthesisers, applications to modulation and demodulation.

Covers oscillator starting and stopping control, direct frequency synthesisers, amplitude and phase angle modulation and demodulation arrangements, mixing; frequency changing, and modulation and demodulation aspects in general. Details of construction and layout aspects of microwave and HF circuits.

Automatic digital phase/frequency-control and synchronisation for pulses. Acoustic wave devices.
ISSN 1463-7987