Grating assembly with bi-directional bandwidth control

A bi-directional bandwidth controlled grating assembly comprising:

• A) a grating defining a lined surface and a first end and a second end;
• B) a first end plate attached to said first end and extending in a direction away from said lined surface;
• C) a second end plate attached to said second end and extending in a direction away from said lined surface and having a threaded channel;
• D) a spring housing connected to said first end plate and defining a first pressure surface and a second pressure surface;
• E) an adjustment rod having a threaded section threaded into said threaded channel of said second end plate and extending into said spring housing;
• F) an adjustment rod piston fixed on said adjustment rod;
• G) a first compression element mounted between said first pressure surface and said adjustment rod piston;
• H) a second compression element mounted between said second pressure surface and said adjustment rod piston;
• wherein said lined surface is made more concave or less convex by an action of screwing said adjustment rod in a direction to cause it to extend into said spring housing and said line surface is made more convex or less concave by an action of screwing said adjustment rod in a direction to cause it to withdraw from said spring housing.