Comparison of various numerically controlled oscillators

Kadam, S.; Sasidaran, D.; Awawdeh, A.; Johnson, L.G.; Soderstrand, M.A.

doi:10.1109/mwscas.2002.1187005

Cited by 14 publications

(7 citation statements)

References 2 publications

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“…The integrator computes a phase slope that is mapped to a sinusoid (possibly complex) by the LUT. This value is presented to the address port of the LUT that performs the mapping from phase-space to time [15].…”

Section: Numerically Controlled Oscillatormentioning

confidence: 99%

An Efficient FPGA-based Frequency Shifter for LTE/LTE-A Systems

Figueiredo¹

2019

Preprint

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The Physical Random Access Channel (PRACH) plays an important role in LTE and LTE-A systems. It is through the PRACH channel that the user equipment (UE), based on eNodeB's timing estimates, aligns its uplink transmissions to the eNodeB's uplink and gain access to the network. One of the initial operations executed by the PRACH receiver at eNodeB side is the translation of the PRACH signal back to base band, $i.e.$, center the PRACH signal around DC. This operation is a necessary step for preamble detection and can be carried out through a time-domain frequency shift operation. Therefore, in this paper we present the hardware architecture and implementation details of a configurable and optimized FPGA-based time-domain frequency shifter. It is a hardware-efficient and accurate architecture for converting the relevant received PRACH signal into base band before further signal processing. The architecture is manly based on a customized Numerically Controlled Oscillator (NCO), which is used for generating complex exponentials employing only adders, a Look-Up Table (LUT) and plain logic resources. The main advantage of the proposed hardware architecture is that it completely eliminates the need for storing a large number of long complex exponential sequences by employing a single LUT and exploiting quarter wave symmetry of the basis waveform. Our simulation results show that the proposed customized NCO architecture provides high Spurious Free Dynamic Range (SFDR) signals using a minimal amount of FPGA resources. Moreover, the proposed architecture exhibits spur-suppression ranging from 62.13 to 153.58 dB without using Taylor Series correction.

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Section: Numerically Controlled Oscillatormentioning

confidence: 99%

An Efficient FPGA-based Frequency Shifter for LTE/LTE-A Systems

Figueiredo¹

2019

Preprint

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“…The NCO (Kadam, Sasidaran, Awawdeh, Johnson, & Soderstrand, 2002) needs a digital sine-wave generator that can be implemented using either a look-up table or the CORDIC method. In our implementation, we use the look-up table.…”

Section: The Numerically Controlled Oscillatormentioning

confidence: 99%

A dynamically reconfigurable cell array for software-defined radio

Shan

Han

et al. 2014

International Journal of Electronics Letters

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“…The typical NCO [1]with zero phase offset has two components: the phase accumulator, and sine-cosine lookup table. A typical NCO circuit with zero phase is shown in Figure 1.…”

Section: Typical Ncomentioning

confidence: 99%

An Optimal Algorithm for Designing NCO Circuit in Mobile Communication Systems

Huang

2009

2009 WRI International Conference on Communications and Mobile Computing

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In this paper, we present an algorithm named Coordinate Rotation Digital Computer (CORDIC) for designing the Numerically Controlled Oscillator (NCO) used in Digital Down Converters (DDC) of GSM applications.Synthesizing with Synopsys EDA tools shows that CORDIC can significantly reduce the die size by about 30%, thus greatly expands the application fields of NCO. Meanwhile, this paper analyzes the problems in engineering implementation and points out the future research directions.

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Comparison of various numerically controlled oscillators

Cited by 14 publications

References 2 publications

An Efficient FPGA-based Frequency Shifter for LTE/LTE-A Systems

An Efficient FPGA-based Frequency Shifter for LTE/LTE-A Systems

A dynamically reconfigurable cell array for software-defined radio

An Optimal Algorithm for Designing NCO Circuit in Mobile Communication Systems

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