76002 Newport Ratio / Log Unit

The Newport / Oriel 76002 Ratio / Log Unit is a microprocessor-based instrument operating on two signals. It provides linear or logarithmic functions of each signal independently and/or the ratio of the two signals.

Each input signal goes through analog offset and gain controls and then through a low-pass filter before being converted to a digital number in an analog to digital converter. The microprocessor then operates on the digital signal according to the function selected on the function switch. Since signal processing is digital, the accuracy of ratio and logarithmic operations is well defined. These processing circuits are not subject to analog drift.

Two function switches are provided, one for each output signal. Any of the 10 functions may be selected for either output signal. Thus great versatility of data taking and recording is achieved. For example, input signal A may be used as output 1 and log A/B as output 2. The analog signals are suitable for recorder or oscilloscope presentation. A digital panel meter monitors each output channel separately. The digital information is also available in multiplexed BCD format for computer interfacing.