A transceiver comprising: a transmitter, a receiver; and an adjustable filter provided in the transmitter; an adjustable filter provided in the receiver, and a transceiver control apparatus, each adjustable filter (714,702) having at least one transition band adjustable under control of the transceiver control apparatus to suit spectrum block operating assignments, wherein, for a boundary between adjacent spectrum blocks with differing operations, the transceiver control apparatus is configured to: a) in a first configuration, place a transition band of the at least one transition band of the transmitter's adjustable filter on a first side of the boundary and place a transition band of the at least one transition band of the receiver's adjustable filter on the first side of the boundary; and b) in a second configuration, place the transition band of the at least one transition band of the transmitter's adjustable filter on a second side of the boundary and place the transition band of the at least one transition band of the receiver's adjustable filter on the second side of the boundary, wherein, for a) and b), placing the transition bands is based on a channel assignment for one or more of the adjacent spectrum blocks to accommodate utilization of edge channels in the adjacent spectrum blocks. a transmitter, a receiver; and an adjustable filter provided in the transmitter; an adjustable filter provided in the receiver, and a transceiver control apparatus, each adjustable filter (714,702) having at least one transition band adjustable under control of the transceiver control apparatus to suit spectrum block operating assignments, wherein, for a boundary between adjacent spectrum blocks with differing operations, the transceiver control apparatus is configured to: a) in a first configuration, place a transition band of the at least one transition band of the transmitter's adjustable filter on a first side of the boundary and place a transition band of the at least one transition band of the receiver's adjustable filter on the first side of the boundary; and b) in a second configuration, place the transition band of the at least one transition band of the transmitter's adjustable filter on a second side of the boundary and place the transition band of the at least one transition band of the receiver's adjustable filter on the second side of the boundary, a) in a first configuration, place a transition band of the at least one transition band of the transmitter's adjustable filter on a first side of the boundary and place a transition band of the at least one transition band of the receiver's adjustable filter on the first side of the boundary; and b) in a second configuration, place the transition band of the at least one transition band of the transmitter's adjustable filter on a second side of the boundary and place the transition band of the at least one transition band of the receiver's adjustable filter on the second side of the boundary, wherein, for a) and b), placing the transition bands is based on a channel assignment for one or more of the adjacent spectrum blocks to accommodate utilization of edge channels in the adjacent spectrum blocks.