• Journal of the Korea Institute of Military Science and Technology
• /
• v.15 no.1
• /
• pp.66-74
• /
• 2012

The virtual target signal generator was developed to verify the shipborne tracking radar performance. It was used to DRFM(Digital RF Memory) method to generate the virtual moving targets. The target signal includes Doppler shift and RCS according to the target motion. And the signal generator can make jamming signal and clutter to test shipborne radar performance at real environmental condition. This paper described the functional diagram and the hardware configuration items to meet the test requirements for the tracking radar. And it showed the critical design points for the sub-systems. The signal generator which was developed in this paper shared the operational information of the radar with the radar command and control part. To test the frequency agility of the radar, it had the local oscillator which could do high speed frequency switching according to radar information. By communicating between the signal generator and the radar command and control part, the local oscillator of signal generator could be controlled every pulse. It reduced the instantaneous bandwidth of signal generator and minimized the spurious. So it lowered the probability of generating wrong targets.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.2632-2635
• /
• 2003

This paper designs a software signal generator for the new GPS L2 civil signal. The CM/CL code and the message structure of L2CS described in GPS ICD PPIRN-200C-007 are used in designing the signal generator. The output of the GPS signal generator is designed as the sampled IF data with the sampling frequency 5.7MHz and stored in the binary data format. By analyzing both the spectrum characteristics of the output signal and the correlation properties of the CM/CL code, the validation of the designed GPS signal generator is shown. It should be mentioned that the modeling of the GPS satellite constellation and the error sources remains for implementing the software space segment of GPS.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.2
• /
• pp.211-215
• /
• 2006

In this paper, design and applications of a generalized, versatile and customizable IF signal generator that can model the modernized GPS and Galileo signal is given. It generates IF sampled data that can be directly used by a software receiver. Entire constellation of satellites which is independent of satellite-user geometry is easily determined using a real or simulated ephemeris data. Since the IF center frequency, sampling frequency and quantization bit number are user location dependent parameters, their effects are also considered in IF signal generator. The generalized IF signal generator will be very well suited for the development phase of a software receiver due to its versatility. The full access to the sampling frequency, front-end filter definition and ADC parameters also offers a great opportunity for cost-effective analysis of tracking loops and error mitigation techniques at the receiver level. Interference sources can be easily added to the generator to simulate specific environments. This software IF signal generator can also be used to feed a multi-frequency multi-system software receiver for the prototyping of a combined GPS/Galileo receiver. The test result using the generated signals and a real software receiver shows the effectiveness of the implemented IF signal generator.

• Journal of Positioning, Navigation, and Timing
• /
• v.1 no.1
• /
• pp.29-34
• /
• 2012

A software GNSS signal generator for the GPS L1/L2/L5 and Galileo E1/E5 signals is proposed in this paper. And this signal generator is designed and implemented with several components by considering the reuse and expansion of components for similar GNSS signals. The characteristics of the reusability of the components are confirmed with the carrier generation and the band-pass filter components. And the functionality of the GNSS multi-band IF signal generator is validated by using the commercial software GPS L1 receiver, and the performance of signal acquisition, tracking and accuracy of horizontal position error are analyzed for this validation. As a result, the GPS L1 signal generator operates successfully and it could be expected that other signal generators also operate well because most of components are the same as those of the GPS L1 signal generator.

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.575-578
• /
• 2004

The performance of an active power filter(APF) depends on the inverter characteristic, the control method, and the accuracy of reference signal generator. The accuracy of reference generator is the most critical item to determine the performance of active power filter. This paper introduces a novel reference signal generator composed of improved adaptive predictive filter. The performance of proposed reference signal generator was first verified through a simulation with MATLAB. Furthermore, the application of feasibility was evaluated through experimenting with a single-phase APF prototype based on the proposed reference generator, which was implemented using the TMS320C31 floating-point signal processor. Both simulations and experimental results confirm that our reference signal generator can be used successfully in practical active power filters.

• Journal of Satellite, Information and Communications
• /
• v.8 no.2
• /
• pp.88-93
• /
• 2013

The wideband chirp signal generator to enhance the resolution of synthetic aperture radar of obtaining the earth observation image is needed. This paper deals with designing, manufacturing and testing the wideband digital chirp signal generator having high resolution for LEO earth observation satellite. The wideband digital chirp signal generator is implemented with the memory-map based structure which is mostly applied in the satellite, and consists of the digital module to generate the digital chirp signal and the RF module to perform the quadrature modulation. The I/Q signals stored in the memory of the digital module are D/A converted and delivered to be quadrature modulated with the reference signal of 1275 MHz in the RF module. Furthermore, the test bench and GUI to validate the signal generator function are also developed. It is found that the requirement of 144 MHz bandwidth for the digital chirp signal generator is well met. Finally it is noteworthy that the distortion occurred in the chirp signal generator was compensated by the pre-distortion compensation.

• Journal of Satellite, Information and Communications
• /
• v.10 no.1
• /
• pp.71-76
• /
• 2015

In this paper, we developed the hardware GPS signal generator for generating a satellite navigation signal synchronized with Live GPS signal signals and analyzed the performance of signal genterator thorough the experiment For a hardware implementation of the GPS navigation signal synchronous generator, the GPS module may receive a GPS signal in order to generate the same signal as the operation that is transmitted from the current GPS satellite and the synchronized time information and the GPS satellites using the Novatel Inc. OEMStar.In. For generating the GPS synchronization signal, the GPS navigation signal generator was adjusted to a reference clock using the GPS clock synchronous information provided by the GPS receiving module and GPS signals also generated in consideration of the delay of the internal hardware of the generator. In this paper, we analyzed the effect of the receiver via the signal switching between Live GPS signal and generates a signal to measure the performance of the GPS navigation synchronization signal generator. It was confirmed that by the seamless operation of the signal even the moment that the switching of the generated signal from Live GPS signal has occurred through experimentation.

• Proceedings of the KIEE Conference
• /
• 2003.04a
• /
• pp.212-216
• /
• 2003

The performance of active power filter depends on the inverter characteristic, the control method, and the accuracy of reference signal generator. The accuracy of reference generator is the most critical item to determine the performance of active power filter. This paper introduces a novel reference signal generator composed of improved adaptive predictive filter. The performance of proposed reference signal generator was verified by means of simulation with MATLAB. The simulation result confirm that the proposed reference signal generator can be utilized for the active power filter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.10a
• /
• pp.336-339
• /
• 2007

A chaos signal is used in all fields like engineering, a medical science and a biology very much, and study regarding the digital communication system that used a recent chaos signal is consisting actively. Applied a chaos signal in a digital communication system, and this paper designed six chaos signal generator to have been composed of by nonlinear equations as used System Generator, and implemented hardware to FPGA. Loaded bit stream to a FPGA board in order to verify this design to Hardware co-simulation from these results. Also, compared as investigated the maximum action frequency through timing analysis and resource of logic in order to evaluate performance of six chaos generator.

• Journal of Magnetics
• /
• v.14 no.2
• /
• pp.97-100
• /
• 2009

A new eddy current testing probe was developed to separate the eddy current signal distortion caused by permeability variation clusters and ordinary defects created in steam generator tubes. Signal processing circuits were inserted into the probe to increase the signal-to-noise ratio and allow digital signal transmission. The new probe could measure and separate the magnetic phases created in the steam generator tubes in the operating environment of a nuclear power plant. Furthermore, the new eddy current testing probe can measure the defects in steam generator tubes as rapidly as a bobbin probe with enhanced testing speed and reliability of defect detection.