摘要:
A clock signal is generated, from a biphase modulated, digital signal, by means of two samples (TF, TB) per symbol interval, T. This pair of samples are spaced at about T / 4. The clock is generated by, firstly, shifting the pair of samples (TF, TB) until one of them (TF) is very close to the zero - crossing point of the biphase signal. The other sample (TB) will then be located at a maximum or minimum. During this procedure, the separation of the two samples remains fixed at T / 4. The separation is then made variable. In this way, TF can track the zero crossing point while TB remains at the maximum or minimum, despite jitter in the incoming signal.
摘要:
Arrangement for generating pulse code modulation values in a telephone set, comprising a microprocessor (1) which includes a working store, in which the microprocessor and the working store are connected by means of a data bus (5) and an address bus (6), further including an output circuit (3) for outputting the pulse code modulation values, an output memory connected thereto for storing the pulse code modulation values to be output, the working store and the output memory being incorporated in a single memory circuit (2). The arrangement is preferably structured in such a way that it comprises addressing means for generating, in response to the microprocessor's addressing of a random location of the output memory, an address of an output memory location to be read out.
摘要:
The invention relates to an arrangement comprising a controllable clock signal source (1) and a decision circuit (8) for determining the polarity of a received biphase signal at two successive sampling instants in a single symbol interval. The arrangement likewise comprises a phase detector (35) with a first comparator (16) to compare the polarity samples at the two sampling instants with each other. The phase detector generates a control signal for adjusting the frequency and phase of the adjustable clock signal source (1) in response to the output signal of the first comparator. Furthermore, the arrangement comprises a second comparator (28) for comparing polarity samples at the same relative sampling instant in two successive sampling instants with each other. According to the invention the second comparator (28) will inhibit phase detector (35) in response to the output signal of this second detector. In the case of false synchronization, the output of phase detector (35) will continue to present the same signal value, so that automatically an adjustment is made of the instant of correct synchronization. This adjustment is carried out by a VCO (3) and/or phase shifter means (12).
摘要:
A method of discriminating among frequencies of an a.c. voltage by means of a processor linked to the a.c. voltage, wherein, after detection of a first zero-crossing of the a.c. voltage, a looped program is initiated, the loop comprising a counter counting the number of loop cycles until a second zero-crossing is detected. Then it is determined in which preset interval the count is situated, each interval corresponding with a possibly occurring 10 frequency.
摘要:
Arrangement for generating pulse code modulation values in a telephone set, comprising a microprocessor (1) which includes a working store, in which the microprocessor and the working store are connected by means of a data bus (5) and an address bus (6), further including an output circuit (3) for outputting the pulse code modulation values, an output memory connected thereto for storing the pulse code modulation values to be output, the working store and the output memory being incorporated in a single memory circuit (2). The arrangement is preferably structured in such a way that it comprises addressing means for generating, in response to the microprocessor's addressing of a random location of the output memory, an address of an output memory location to be read out.
摘要:
The invention relates to an arrangement comprising a controllable clock signal source (1) and a decision circuit (8) for determining the polarity of a received biphase signal at two successive sampling instants in a single symbol interval. The arrangement likewise comprises a phase detector (35) with a first comparator (16) to compare the polarity samples at the two sampling instants with each other. The phase detector generates a control signal for adjusting the frequency and phase of the adjustable clock signal source (1) in response to the output signal of the first comparator. Furthermore, the arrangement comprises a second comparator (28) for comparing polarity samples at the same relative sampling instant in two successive sampling instants with each other. According to the invention the second comparator (28) will inhibit phase detector (35) in response to the output signal of this second detector. In the case of false synchronization, the output of phase detector (35) will continue to present the same signal value, so that automatically an adjustment is made of the instant of correct synchronization. This adjustment is carried out by a VCO (3) and/or phase shifter means (12).