About TEDS (TETRA2) Modulation Analysis

89601AYAC (89601B-BHA) TEDS Demodulation adds TETRA Trans-European Trunked Radio. A communications system standard. Enhanced Data Service (TEDS) signal demodulation capability to your 89600 VSA software. TEDS is an air interface standard (Physical Layer OSI Open System Interconnect layer 1) between fixed network equipment (Downlink slot) and subscriber units (Uplink slots) and provides wireless communications between these two functional groups. Typical TEDS applications are for Public Safety where TEDS increases TETRA data speeds up to 30 - 150kbit/s.

TEDS delivers a flexible bit rate in 25, 50, 100, and 150kHz radio channel bandwidths using multicarrier coherent time division multiple-access (TDMA Time Division Multiple Access: A technology for digital transmission of radio signals between, for example, a mobile telephone and a radio base station. In TDMA, the frequency band is split into a number of channels which in turn are stacked into short time units so that several calls can share a single channel without interfering with one another. Networks using TDMA assign 6 timeslots for each frequency channel. TDMA is also the name of a digital technology based on the IS-136 standard. TDMA is the current designation for what was formerly known as D-AMPS.) modulation. This flexibility allows TEDS to optimize performance by allowing higher system data throughput under good signal conditions, while still supplying significantly better throughput than current systems operating under weaker signal conditions. The downlink transmission mode is continuous, while the uplink transmission mode is pulsed on a slot-by-slot basis.

With 89601AYAC, you can demodulate TEDS-modulated signals, both in downlink and uplink directions. The demodulator parameters are user-definable, giving you the ability to customize the demodulator to measure and analyze non-ideal signals. You can choose from four TEDS slot formats (Normal Downlink, Normal Uplink, Random Access, and Control Uplink), three quadrature amplitude modulation (QAM Quadrature Amplitude Modulation) types (M-4QAM, M-16QAM, M-64QAM), and four channel bandwidths (25kHz, 50kHz, 100kHz, and 150kHz).

For measurement and analysis, you can display traces for the composite signal (including Error Summaries) and traces for selected Subcarriers (such as Constellation Diagrams). Additional demodulation parameters let you adjust for Search Length and what to include for error vector magnitude (EVM Error vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format.) errors (such as Header Symbols, Droop, and Pilot Tracking). Development parameters include Filter Alpha, Time Scale Factor, and Mirror Frequency Spectrum.

TEDS provides many unique Time Domain and Frequency Domain trace data results including the following composite trace results:

Using Subcarrier selections, you can view individual trace results for a selected subcarrier: