Comtech EF Data MCED-100 - Manual (Page 20)

MCED-100 MetaCarrier Embedding Device Revision 1
Introduction MN-MCED100
1–2
1.2 Functional Description
Figure 1-2. MCED-100 Connection Example
At the source of the transmission carrier (transmit), the MCED‐100 may be connected inline
between the modulator (producing the transmission carrier) and the upconversion equipment
before transmission. An example of this setup is shown in Figure 1‐2. The MCED‐100
automatically determines the carrier’s characteristics:
• Center frequency • Symbol Rate • Power Level
Once the transmission carrier’s characteristics are automatically obtained by the MCED‐100
receiver section, the MCED‐100 processor then creates a composite carrier by first sizing the
appropriate MetaCarrier, and then by adding the spread spectrum CID (with power spectral
density approximately 22 dB below the transmission carrier’s spectral power density) to the
transmission carrier.
The size of the MetaCarrier is determined through digital signal processing techniques, resulting
in two (2) discrete sizes of MetaCarriers being combined with the transmission carrier. The
MetaCarrier sizes are available as follows:
Original Carrier Embedded MetaCarrier
≥256 ksps 224 kcps
128 ksps to < 256 ksps 112 kcps
As shown in this table, the MetaCarrier is sized to be no more than 87.5% of the bandwidth of
the transmission carrier. In all configurations of the combined carrier, the MetaCarrier raises the
transmission power less than 0.1 dB above the original carrier.
The CID message is composed of the following information:
• MAC Address • Latitude • Longitude
• Operator • Manufacturer • Telephone Number
• Center Frequency • Symbol Rate • Custom Message