Using a new parity-check matrix, a class of convolutional codes with a designed free distance is introduced. This new class of codes has many characteristics of BCH block codes, therefore, we call these codes BCH convolutional codes.

Motivated by applications in cryptology, Wei (1991) introduced the concept of a generalized Hamming weight for a linear block code. In this correspondence, we define generalized Hamming weights for the class of convolutional codes and we derive several of their basic properties. By restricting to convolutional codes having a generator matrix G(D) with bounded Kronecker indices we are able to derive upper and lower bounds on the weight hierarchy.

It is well known that a convolutional code is essentially a linear system defined over a finite field. In this paper we elaborate on this connection. We define a convolutional code as the dual of a complete linear behavior in the sense of Willems (1979). Using ideas from systems theory, we describe a set of generalized first-order descriptions for convolutional codes. As an application of these ideas, we present a new algebraic construction for convolutional codes.