Long pulsed neutron sources are being actively considered for next the next generation of high powered sources, such as the ESS and the SNS second target station.  New instrumentation concepts will be required to effectively utilize the full spectrum of neutrons generated by these sources. Neutron diffractmeters, which utilize time-of-flight techniques for wavelength resolution, are particularly problematic.  To obtain resolution comparable to short pulsed sources either unrealistically long initial flight paths or a drastic reduction in flux using choppers is required.  We will describe an instrument for a long pulsed source that provides resolution comparable to that obtained on short pulsed sources without the need to either utilize unrealistically long incident flight paths or to drastically sacrifice intensity to reduce the pulse length or bandwidth.  We accomplish this by utilizing high speed choppers to impose a time structure on the spectrum of incident neutrons.  By strategically positioning these choppers the response matrix assumes a convenient form that can be inverted allowing the measured TOF spectrum to be used to obtain the diffraction pattern of the sample. We will compare the performance of this instrument to other possible diffraction instruments that could be utilized on a long pulsed source.