A SAW device (30) tapped delay line includes an apodized input IDT (inter-digital transducer) (36) and a plurality of substantially identical unapodized output IDTs (32) arranged to receive, after delays which successively increase by an amount T, a SAW propagated from the input IDT. Each output IDT is terminated with a low impedance which is constituted by the low input impedance of a buffer amplifier (34), to minimize acoustic regeneration by the output IDTs. Grounded dummy fingers with the same metallization ratio as the output IDTs are provided between adjacent output IDTs to provide a constant SAW velocity. The delay line is particularly suited to use in an equalizer of a microwave radio transmission system, in which the delay T is the inverse of the symbol rate of the system. Intermediate frequency automatic time domain equalizer (IF ATDE) arrangements using the SAW device tapped delay line are described.