SPECTROPHOTOMETER

摘要

1 PHP. 1236 A dual beam ratio recording spectrophotometer has signal processing circuitry for determining the transmittance of a substance. The signal processing circuitry has a bandwidth which is dependent on the magnitude of the radiation passing through a reference cell and includes control logic circuitry which produces a pulse on line m whose width is proportional to the square of the magnitude of the radiation detected when the beam passes through the reference cell. A sample and hold circuit whose sample time is controlled by the pulse on line m samples the output of an integrator which produces at regular intervals a signal representative of the transmittance of a substance. Thus the response time of the sample and hold circuit and hence the bandwidth of the signal processing circuitry depends on the magnitude of the radiation passing through the reference cell.