LSI Processor for Digital Signal Processing and Its Application to 4800 Bit/s Modem

Murano, K.; Unagami, S.; Tsuda, Toshitaka

doi:10.1109/tcom.1978.1094105

Cited by 10 publications

(3 citation statements)

References 6 publications

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“…Because of the limited computing power available, the quadrature component of the received signal is not derived digitally but is generated by an analog 90-degree phase-shift network. Combined with the in-phase component, it forms the analytic signal [8] y(t) = 2 sit -m expJl27Tif" + Af)t + <pj + k wit), (4) where sit) is the overall baseband equivalent impulse response, generally complex, w(t) is complex filtered noise, and A/ represents frequency shift.…”

Section: General Receiver Structurementioning

confidence: 99%

“…The general aspects of microprocessor modem implementations are well covered in the communications literature [2][3][4], The algorithms and procedures that are reported commonly apply to data rates equal to or greater than 4800 bits/s, where adaptive equalization, precise timing, and carrier phase tracking are of crucial importance for good performance [5]. A microprocessor without multiplication capability is used in [3] to handle all the functions of a 4800-bit/s modem, and processing cycle reduction is obtained with the aid of decision-feedback equalization.…”

Section: Introductionmentioning

confidence: 99%

“…A microprocessor without multiplication capability is used in [3] to handle all the functions of a 4800-bit/s modem, and processing cycle reduction is obtained with the aid of decision-feedback equalization. In [2] and [4], LSI processors designed for performing specialized digital filtering operations are described. Figure 1 General microprocessor architecture.…”

Section: Introductionmentioning

confidence: 99%

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A 2400-Bit/s Microprocessor-Based Modem

Godard

Pilost

1981

IBM J. Res. & Dev.

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This paper describes the main characteristics of a new microprocessor-implemented2400-bitls data modem, the IBM 3863. In addition to the execution of signal processing tasks, the microprocessor provides a variety of other significant functions such as diagnostics and aids in network problem determination. The lack of hardware multiplication capability imposes certain constraints in the design of the signal processing algorithms. The analytical approach and computational techniques, based on the processing of signals in polar coordinates, which are used to circumvent these constraints, are described. It is shown in particular that timing phase control, carrier recovery, and adaptive equalization can be achieved at the receiver by processing only the phase of the sampled signal. Additionally, experimental results are presented which demonstrate the superiority of this design over conventional coherent demodulators.At the relatively low data rate of 2400 bits/s, line distortions and impairments are usually not severe enough to require the implementation of sophisticated signal processing techniques, which explains why most 2400-bit/s modems are only equipped with compromise, possibly manually selectable, equalizers.

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Section: General Receiver Structurementioning

confidence: 99%