2) EP 0 402 973 B1 Philips transmission patent
Digital transmission system, transmitter and receiver for use in the transmission system, and record carrier obtained by means of the transmitter in the form of a recording device.
Claim 1:
Technical summary of text:
A digital transmission system that
- Comprises:
- a transmitter (1)
- Comprising an input terminal (2) for receiving a wide-band digital signal
- Comprising an output terminal (7)
- Constructed to supply a second digital signal to the output
- a medium (4) (carrying the second digital signal)
- a receiver (5)
- Comprising a decoder
- with an input (10) receiving the second digital signal
- with an output coupled to an output terminal (8), supplying the original wide-band digital signal
- Transmits using a second digital signal that can be described as a sequence of 'frames':
- 'frames' consist of multiple 'information packets' (IP)
- Each 'information packet' contains N bits (N > 1)
- The 'frames' all start with a piece of synchronisation information
- The signal is obtained by encoding a digital signal S with a sampling frequency Fs
If we define:
- B as the number of 'information packets' in a 'frame'
- BR as the bitrate of the encoded digital signal
- Ns as the number of samples of the original signal S corresponding to the information contained in one 'frame' of the encoded signal
- N ans Fs as described above
The relation P = ( BR / N ) * ( Ns / Fs ) gives P such that:
- If P is an integer, it is equal to B
- If P is not an integer, B is the integer below P. In other frames B is the integer above P, whereas the average framerate of the encoded signal is substantially equal to Fs/Ns
Comments
The system claimed is in part identical to patent 0 660 540 B1. The mentioned 'decoder' is in fact the decoder claimed in that patent. Hence, the signal described is exactly the same. For a description of and some comments on that signal, please refer to the technical summary of that patent.
Note that the formula for P shown in both patents are algebraically identical!
The second digital signal is shown in italics to stress that it is the same signal.
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