

Abba
Pop in this context means middle of the road music - not too challenging and appealing to many different tastes.The Carpenters and Abba are examples of pop bands.
Synth pop is characterised by the use of synthesisers (brought out by Moog in 1970) to bend the sound. Tangerine Dream was an early synth band, but the most influential exponents of synth pop were the German band Kraftwerk who used powerful 'industrial' sounds: Autobahn (1974) was one of their many hits.

Depeche Mode
Synth continued in the late 1970s with Gary Numan and David Bowie, and into the 1980s with bands like Depeche Mode, Orchestral Manoeuvres in the Dark, New Order and Visage.