1
Willem F Druyvesteyn, Abraham Hoogendoorn, Leon M Van De Kerkhof, Raymond N J Veldhuis: Coder for incorporating an auxiliary information signal in a digital audio signal, decoder for recovering such signals from the combined signal, and record carrier having such combined signal recorded thereon. U S Philips Corporation, Leroy Eason, November 3, 1992: US05161210 (254 worldwide citation)

The audio signal is divided into frequency sub-bands, the sub-band samples are quantized according to a predetermined quantizing criterion, and the quantized samples in one or more sub-bands are summed with samples of the auxiliary signal in such sub-bands, the auxiliary signal sample in a sub-band ...


2
Abraham Hoogendoorn, Franz Kuchar: System for reproducing information signals on a magnetic tape which incrementally adjusts, in a plurality of steps the speed of the magnetic tape and the positioning and rotational speed of the magnetic head upon a change of mode. U S Philips Corporation, Thomas A Briody, Jack Oisher, William J Streeter, January 13, 1987: US04636874 (41 worldwide citation)

A system (1) for reproducing information signals recorded on a magnetic tape (2) in oblique tracks (S) in different modes of operation with different tape speeds v(n) includes a tape drive device (13), which is switchable in respect of the tape speed, at least one magnetic head (K1, K2), which is ro ...


3
Abraham Hoogendoorn, Gerardus Lokhoff: Apparatus for recording an audio signal with protection against re-recording thereof, and recording apparatus which indicates the presence of such protection. U S Philips Corporation, Leroy Eason, January 21, 1992: US05083224 (32 worldwide citation)

Low-frequency components of the left and right channels of the audio signal to be recorded are derived by means of filters (3, 4). First and second auxiliary signals are added to such low-frequency components in such a way that during reproduction of the audio signal so recorded, including the first ...


4
Kornelis A Immink, Abraham Hoogendoorn: Control loop. U S Philips Corporation, Thomas A Briody, William J Streeter, Algy Tamoshunas, August 25, 1981: US04286318 (27 worldwide citation)

A control loop provided with a control unit for realizing a transfer characteristic having a number of peaks at a fundamental frequency and harmonics thereof. The control unit comprises a memory device for digitally storing a number of samples of the error signal appearing in the control loop during ...


5
Rudolf A Van Doorn, Stephanus J M Van Beckhoven, Gerardus W A Akkermans, Franciscus J R Verhallen, Abraham Hoogendoorn: Recording device with temperature-dependent write-current control. U S Philips Corporation, Edward W Goodman, October 3, 1995: US05455717 (17 worldwide citation)

A device for recording an information signal on a magnetic record carrier (2) includes a write amplifier (3), a magnetic head (4) of the magnetoresistive type, and a compensation circuit for controlling the amplitude of the write current in dependence upon temperature variations which occur during r ...


6
Peter Haubrich, Abraham Hoogendoorn, Uwe Jahnke: Apparatus for reproducing information recorded in a plurality of adjacent tracks. U S Philips Corporation, Thomas A Briody, Robert T Mayer, Algy Tamoshunas, March 27, 1984: US04439799 (13 worldwide citation)

A reproducing apparatus for information signals recorded in inclined tracks together with tracking signals whose frequency changes from track to track in a cyclic sequence, comprises a variable-frequency signal generator for the generation of track selection signals, from which together with the cro ...


7
Abraham Hoogendoorn, Robert Emile Johan VAN DE Grift, Theodorus Jozef VAN Kessel: Analog-digital converter. U S Philips Corporation, Frank R Trifari, Daniel R McGlynn, November 8, 1977: US04057796 (10 worldwide citation)

An analog-digital converter in which a capacitor is charged or discharged by a reference current with the aid of transistor switches, a continuous current flows through the capacitor which is determined by an input difference voltage. One side of the capacitor is connected via a comparator to a flip ...


8
Johannes C A Muller, Abraham Hoogendoorn: Magnetic head configured to read and/or write information on digital and analog form. U S Philips Corporation, John C Fox, November 3, 1998: US05831798 (8 worldwide citation)

A magnetic tape apparatus intended for consumer use includes at least one digital head with nine digital transmission gaps for reading and/or writing compressed digital information in longitudinal tracks on a magnetic tape. The apparatus also includes electronic circuitry for compressing the digital ...


9
Jan Dewolf, Gerardus Lokhoff, Abraham Hoogendoorn: Transmission system, and transmitter and receiver used in the transmission system for transmitting and receiving digital signals containing modulated bit allocation information. U S Philips Corporation, Richard A Weiss, December 20, 1994: US05375171 (8 worldwide citation)

Transmission system, and transmitter and receiver for use in the transmission system for transmitting and receiving digital signals containing modulated bit allocation information. The transmitter encodes a wide-band digital signal into subband signals which are each made up of successive signal blo ...


10
Abraham Hoogendoorn, Gerardus C P Lokhoff: Reproducing device used with a record carrier containing two sides recorded in opposite directions that determines the selection of particular read back characteristics. U S Philips Corporation, John C Fox, September 24, 1996: US05559642 (7 worldwide citation)

Digital information recorded in a track (T.sub.a.i) on a tape-like magnetic record carrier (20) can be read out again when the record carrier is transported in a specific direction. The transport direction of the record carrier when the information is recorded may be similar or opposite to the direc ...