I read Network Maintenance and Troubleshooting Guide book and in paragraph where Ethernet frame preamble is explained, it says that except for 100BASE-T4, faster versions of Ethernet are synchronous. Is it possible to keep both data and synchronization signal on the same signal path?
The preamble is simply a series of 1s and 0s that signal the start of a packet. At the end of the preamble is a sfd (start frame delimiter) that signals the actual start of the Ethernet frame. The very next byte is the beginning of the destination MAC address. So yes the synchronization bits (preamble) are on the same signal path.