Delay Line Filter
Original Publication Date: 1962-Apr-01
Included in the Prior Art Database: 2005-Mar-07
AbstractThis device replaces a conventional, tapped delay line filter. The apparatus shown implements the expression: z(t)=delta Q x(t) + beta z (t-k*tao) (A)
Delay Line Filter
This device replaces a conventional, tapped delay line filter. The apparatus shown implements the expression: z(t)=delta Q x(t) + beta z (t-k*tao) (A)
The constants delta and beta are introduced by amplifiers 2 and 6, respectively, and are chosen to suit the bandwidth limitations of the system. The outputs of amplifiers 2 and 6 are combined in summing junction 3 and the sum signal passed through amplifier 4, which has unity gain. The time delay tau is introduced by delay unit 5 in the signal fed from system output 7 to the input of amplifier 6.
Amplifier 6 has a gain beta less than unity.
As the result of the application of a signal represented as x
(t) to its input, a tapped delay line filter produces an output signal represented by the equation: z(t)= /tao/sigma(k=0) B(k) x(t-k*tao), (B) B(k) represents the amplification factor of the weighting device interposed between the kth filter tap and the summing junction which is included in the delay line filter output; tao is a given time interval of length dependent on bandwidth requirements of the system; and x (t-k*tao) is a discrete value of the output signal at the sampling instant (t-k*tao).
The substantial equivalence between the signal produced by this apparatus at output 7, as the result of the application of a signal represented by the expression x (t) to input 1, and the signal produced by the tapped delay line filter and represented in equation B is demonstrated by deriving from A and su...