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Showing papers on "Pulse-position modulation published in 1976"


Patent
22 Jan 1976
TL;DR: In this paper, an encoding and decoding scheme was proposed for a single simple transmission channel with a single clock-pulse generator and a control circuit connected to a shift register receiving the parallel data words and having a feedback, through an inverter, from a serial word output to an additional input which is a serial input for the inverted output signal.
Abstract: An encoding transmitting unit converts parallel data words into timing pulse synchronized serial data words which are supplied to a transmission channel, and a decoding receiving unit receives the transmitted serial data words from the transmission channel. The encoding unit comprises a clock-pulse generator and a control circuit connected to a shift register receiving the parallel data words and having a feedback, through an inverter, from a serial word output to an additional input which is a serial word input for the inverted output signal. The shift register transmits a first pulse train representing the serial data word followed by a second pulse train representing the inverted serial data word. The decoding receiving unit includes a second shift register having a serial data word input receiving the two pulse trains from the transmission channel and having a serial data word output. An inverting exclusive OR gate has one input connected to the serial word output of this register and another input receiving the transmitted pulse trains from the transmission channel. This OR gate monitors the non-equivalence of the first and second pulse trains, to detect transmission errors and transfer the errors, as error signals, to a flip-flop acting as an error signal storage. A receiving register is connected to the shift register of the receiving unit and is operable to evaluate the transmitted data. The error signal storage, upon receipt of an error signal, prevents such evaluation of the transmitted data in the receiving register. The system may be simplified by using a pulse position modulation and may also be used for a pulse duration modulated signal. In the latter case, a synchronization bit is transmitted before each data word. An outstanding feature of the system is that it may be used with a single simple transmission channel.

19 citations


Patent
17 Nov 1976
TL;DR: In this article, a receiver and decoder are disclosed wherein the receiver may be used as a remote control receiver in conjunction with a transmitter transmitting a carrier modulated with an encoded data train of first and second modulation frequencies.
Abstract: A receiver and decoder is disclosed wherein the receiver may be used as a remote control receiver in conjunction with a transmitter transmitting a carrier modulated with an encoded data train of first and second modulation frequencies for first and second modulation patterns. A third modulation pattern may be established by providing successive portions of the first modulation signal and then the second modulation signal during a given time. If the receiver is on the same carrier frequency and is set to receive the same modulation pattern sequence as in the encoded data train from the transmitter, then the receiver has an output which may be used to control some remote load. This may be a garage door operator to open a garage door, for example. The decoder in the receiver is responsive to the modulation signals and a signal discriminator discriminates among the three different modulation patterns or logic conditions of bits. A data comparator is connected to receive the logic conditions of the bits and a programmable switch provides a programmable bit input to the data comparator which compares sequentially bit by bit the information from the encoded data train with the information from the programmable switch to determine if they are the same or different. When a group of bits compares favorably then an output signal is given from the decoder to control the remote load. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

16 citations


Patent
08 Jan 1976
TL;DR: In this article, a digital filter for pulse code modulation signals employs interpolation and can handle a multiplicity of multiplexed PCC modulation channels, but it is not suitable for the use of single-input single-out (SISO) channels.
Abstract: A digital filter for pulse code modulation signals employs interpolation. A digital filter can handle a multiplicity of multiplexed pulse code modulation channels.

15 citations


Patent
26 Nov 1976
TL;DR: In this article, an encoding transmitter is disclosed which includes a modulator providing a means to modulate a carrier wave selectively with a first or a second modulation frequency or pattern to provide first and second modulation patterns respectively.
Abstract: An encoding transmitter is disclosed which includes a modulator providing a means to modulate a carrier wave selectively with a first or a second modulation frequency or pattern to provide first and second modulation patterns respectively. Also a third modulation pattern may be established by providing successive portions of the first modulation frequency and the second modulation frequency during a given time period. A data selector is controlled by data select control signals which are obtained from a counter counting from the first modulation frequency signal. Programmable means include a multi-position switch to program the input channels of the data selector so as to control whether the first or the third modulation pattern is that which modulates the carrier wave during any given unit of time.

13 citations


Patent
07 Jan 1976
TL;DR: In this paper, a pulse code modulation compressor converts linear PCC words into companded PCC modulation words and passes the converted output through a double buffer to allow independent operation of the conversion clock and output clock.
Abstract: A pulse code modulation compressor converts linear pulse code modulation words into companded pulse code modulation words. A read only memory is loaded with a conversion table and used to perform successive approximations for the conversion. The converted output is then passed through a double buffer to allow independent operation of the conversion clock and output clock.

8 citations


Journal ArticleDOI
TL;DR: The development of the colac timer and the Loran Replacement Equipment package has provided two sources of dramatic improvement of the performance of Loran–C transmitting stations: solid state reliability and the ability to have control locally or remotely exerted.
Abstract: The development of the colac timer and the Loran Replacement Equipment package has provided two sources of dramatic improvement of the performance of Loran–C transmitting stations: solid state reliability and the ability to have control locally or remotely exerted. The improvement due to solid state reliability has been well documented over the past several years while the exploitation of the remote control capability has begun with the recent test deployment of a calculator based remote chain control unit. Results to date have indicated that chain control tolerances on the order of 40 nanoseconds can be attained. At the heart of any such tightly controlled system is the requirement for a reliable communications network such as is readily and economically available from commercial sources on the east coast of the U. S. Plans for worldwide implementation, however, hit a snag in the form of the poor reliability of the communications links available at many of the remote or isolated stations such as those of the Central Pacific or Alaskan chains. For these stations the Coast Guard Two Pulse Loran–C Communications system has been developed. The system, consisting of pulse position modulation (PPM) of two of the pulses of a Group Repetition Interval, has only two performance requirements and these are unique among the various Loran–C communications schemes. One requirement is the transmission of short, infrequent control messages which can be received at baseline distances and, in the face of all the classical interference sources of the Loran-C channel, with a small probability of error. A second requirement is that the PPM impact insignificantly, if at all, on the navigation channel, since improved navigational performance is the primary objective of the system. As will be developed, these two requirements are not at all inconsistent. A complete description of the features of the transmission scheme and their effects is presented.

5 citations


Journal ArticleDOI
TL;DR: A transmitter-receiver combination for remote control of a color TV set is described, which generates a 5-bit PPM code for transmission of 32 commands, requires only 5 external components and an 8/spl times/4 single-pole single-throw keyboard.
Abstract: A transmitter-receiver combination for remote control of a color TV set is described. The transmitter is a 1.6/spl times/1.9 mm/SUP 2/ chip in linear bipolar technology. It generates a 5-bit PPM code for transmission of 32 commands, requires only 5 external components and an 8/spl times/4 single-pole single-throw keyboard. Standby power is zero. The receiver is a 3.1/spl times/3.5 mm/SUP 2/ p-MOS chip and allows for a 20-channel selection. It has 3 D/A converters on chip to generate the analog control signals. It also controls the TV receivers AFC and on-screen display.

5 citations


Journal ArticleDOI
TL;DR: In this article, a television experiment with PbSe semiconductor lasers is described, where the authors describe a television system using PPM (Pulse Position Modulation) for TV links, which is believed to be the first time PBSe diode lasers have been used in TV links.

1 citations


Journal ArticleDOI
TL;DR: In this article, the authors describe a communication system using very simple circuits; the system can easily be assembled in any electronics laboratory and serves the purpose of demonstrating to undergraduates the overall picture of information transmission by PPM.
Abstract: The article describes a communication system using very simple circuits; the system can easily be assembled in any electronics laboratory and serves the purpose of demonstrating to undergraduates the overall picture of information transmission by PPM.

1 citations


Journal ArticleDOI
TL;DR: In this paper, a new method for the generation of the multifunction operation W = sign(X).Z(X/Y) m is treated in this paper, which is based on logarithmic function generation by means of log-rate modulation with an exponential carrier signal (Ye -? X t ).
Abstract: A new method for the generation of the multifunction operation W = sign(X).Z(X/Y) m is treated in this paper. The method is based on logarithmic function generation by means of logarithmic pulse width modulation, which is pulse width modulation with an exponential carrier signal (Ye -? X t ). Demodulation is done by feeding the pulse width modulated signal into an integrator which has a logarithmic pulse width modulator in its feedback path. This feedback pulse width modulator has an exponential carrier signal of the form Ze -? W t . Moreover, this logarithmic pulse width modulator in the feedback path also performs the antilog operation. Hence, multifunction operation is accomplished based on the log-antilog principle. The exponent m is equal to the ratio of the inverse of the time constants of the exponential carrier signals for the input and feedback modulators (m = ? w /? x ).Hence, the exponent m can easily be adjusted. Experiments on the analog computer showed that an accuracy of 0.2% of a 1 V full scale was easily obtainable. The frequency response and the signal-to-noise ratio of the system was determined through simulation on a digital computer.