Decimator apparatus for decreasing the word rate of a digital signal of the type employed in digital telephone systems

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG.
1, there is shown a simplified diagram of a telephone communications system employing digital and analog signal paths.
Essentially, a single subscriber A is connected via a digital switching matrix 10 to another subscriber B.
Each subscriber as A has a separate line circuit 20 associated with his subset and to enable communications between the parties.
While subscribers A and B are shown associated with subsets as 21 and 22, it is understood that the subscribers could be trunk locations for connecting to other central offices and so on, and as such, would also require a line circuit as 20.
In order to simplify the explanation, a single line circuit 20 is shown for subscriber A and it is understood that subscriber B has an identical line circuit 20B as does the plurality of additional subscribers not shown in FIG.
1.
For an example of a digital line circuit employed in a switching system, reference is had to U.
S.
Pat.
No.
4,161,633 entitled SUBSCRIBER LINE/TRUNK CIRCUIT issued on July 17, 1979 to Robert Treiber and assigned to the International Telephone and Telegraph Corp.
, the assignee herein.
The telephone subset 21 associated with subscriber A is coupled via a two-wire analog line including tip (T) and ring lines (R) to a two-to-four wire hybrid or converter circuit 16.
The hybrid 16 is a well known component and essentially connects the two wire analog line to a four wire line.
Hence, the output of the hybrid 16 is coupled to two wires shown as a single line and designated as a transmit pair and two wires (single line) designated as a receive pair.
A description of suitable hybrid circuits and operation may be had by referring to a text entitled "Reference Data for Radio Engineers", Sixth edition (1975) Howard W.
Sams, pages 35-16 through 35-20.
A digital hybrid circuit is described in copending U.
S.
patent application, Ser.
No.
903,458 filed on May 8, 1978 and assigned to the assignee herein.
The transmit pair via hybrid 16 is coupled to the input of an analog filter 18