Digital radio systems operate differently than legacy analog systems. Although digital modulation alignments are similar to alignments used in analog radio systems, digital radios require more precise alignment to achieve optimum performance and must be verified for digital modulation performance. Proper alignment can improve systems performance to maximize and deliver the high performance that it was designed to provide. Improper alignments can cause degraded digital modulation accuracy, which has a significant impact on the receiver’s ability to recover digital data. In some instances, this can affect range to the same extent as a 75% reduction in power.
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This study uses statistical data provided through extensive lab testing and through the use of actual recorded digital radio RF transmitter parameters. It shows how modulation alignments of one radio’s transmitter parameters can positively or negatively affect performance of another radio’s receiver. The performance of various radio receivers were measured using popular radios with transmitters that have been aligned using OEM approved techniques. The tests utilized FM deviation meters for aligning modulation balance and modulation-limiting parameters, while accommodating for variations in meter specification and audio filter settings.
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The conclusion from these tests indicates that with a proper understanding of digital radio operations, performance can be significantly improved. The proper setting of audio filter parameters and the use of accurate deviation meters can also improve digital radio performance. Conversely, the use of inaccurate FM deviation meters compounded by improper audio filter settings and lack of knowledge of meter specifications and operation, can dramatically and negatively impact digital radio performance.
For more information, please contact:
MPG Instruments Mauro Cortese – mauro.cortese@mpginstruments.com
