See http://home.alphalink.com.au/~parkerp/projects/projmicro40.htm .
Also: https://aa7ee.wordpress.com/2013/10/19/the-vk3ye-micro-40-dsb-transceiver/ .
designed DSB transceivers are much simpler than SSB rigs as no SSB
filters and mixing to final frequency is needed. They must not be
over-driven to avoid a spreading signal. The PA needs to be linear too.
These issues being carefully considered, you end up with a rig that has
the same bandwidth as an AM rig but with a suppressed carrier. DSB
transmitters are usually received as an SSB signal. The downside is that
if a simple direct-conversion receiver is used then there is no
rejection of stations sitting on the other sideband. So, they are best
on quieter bands, rather than busy HF bands. Bands like 10m, 6m and 4m
are probably good candidates.
Although not impossible, it is quite difficult to demodulate a DSB signal on a simple direct-conversion receiver. DSB rigs are ideal as simple transceivers to communicate with SSB rigs.