Duplicate of the Spanish lesson on CDMA and FSK, numbered 5 and 474 KB in PDF format. It covers code division multiple access and frequency shift keying, two key techniques in wireless and data communications, and is study material rather than a circuit diagram for any named device. Knowing how these schemes work gives useful background when dealing with cellular and RF circuitry. Since another entry has the same name and size, the two are likely the same file and only one needs to be kept for reference.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @canalesquematicos. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.