Abstract: In a receiver for receiving data samples including a sequence of symbol values transmitted across the channel, a baseband processor including a first hypothesize unit developing first sets of hypothetical symbol values, a second hypothesize unit developing second sets of hypothetical symbol values different from the first sets, a parameter estimator receiving the received data samples and the first and second sets of hypothetical symbol values and developing parameter estimates based thereon, and a sequence estimator receiving the developed parameter estimates, the first sets of hypothetical symbol values and a delayed version of the received data samples and developing a sequence of detected symbol values related to the received data samples.

Abstract: A method is disclosed for generating a PCM code set for encoding data by a PCM encoder in a data transmission system having a digital modem with a PCM encoder, a digital signal transmission path, an analogue signal transmission path with a central office line interface portion, and an analogue modem. The method includes the step of determining a minimum signal level distance between adjacent PCM codes of the PCM code set, the minimum signal level distance enabling discrimination by the analogue modem. Then a line interface attenuation of the central office line interface portion is determined. Finally, the PCM code set on the basis of a power limit computed by adding the line interface attenuation to a central office line interface power limit is generated. The invention further relates to an analogue modem to be operated in such a data transmission system.

Abstract: In a telecommunication system where a plurality of user channels are processed in a time-slotted manner, a transmitter and receiver can perform bit error rate measurements for a plurality of user channels by only using one PN-generator (T-PN) and one state memory (ISM). Whenever the beginning of a new time-slot is detected, a last-stored phase state is read out from the state memory (ISM). When detecting the end of the respective time-slot, the phase state then present in the PN-generator (T-PN) is stored into the state memory (ISM) to be used for re-initialization of the PN-generator (T-PN) for the same time-slot in a succeeding frame. Thus, one PN-generator (T-PN) is enough for generating PN-sequences for a great number of user channels.

Abstract: A method and telecommunication system for tracking the carrier phase of a received signal includes the addition of a pilot signal to the data component of the signal prior to modulation and transmission. The pilot signal is specified to have a frequency equal to the inverse of twice a data symbol interval with zero crossings positioned at the midpoint of each symbol interval to avoid interference with the data. The received signal is demodulated to produce a complex data signal from which the pilot signal is detected to provide an estimate of the phase error in the complex data signal. The elimination of the phase error from the complex data signal is accomplished through a corrective phase shift that is equal and opposite to the estimated phase error. A sample timing estimate may also be obtained in a similar manner.