Abstract: A peak detector provides repeatable and accurate measurements of the signal amplitude for variable frequencies of input signals. The peak detector includes a pulse edge generator circuit that generates a pulse edge signal in response to the signal peaks of an input signal and a sampler circuit that is triggered to sample the input signal by the pulse edge signal. The pulse edge generator circuit compares the input signal with a delayed version of the input signal to produce a differential signal and generates the pulse edge signal using the differential signal. An analog or digital sampler is triggered by the pulsed edge signal to measure the information, e.g., peak value, of the input signal. One or more delay circuits may be used to align the edges of the pulsed edge signal with the peaks of the input signal.

Abstract: A transimpedance amplifier system includes a current source, such as a photodiode, coupled between two transimpedance amplifiers, each having feedback circuits with different impedances. Thus, for example, the cathode of a photodiode is coupled to a first transimpedance amplifier while the anode of the photodiode is coupled to the second transimpedance amplifier. Consequently, two voltage gains can be achieved without the use of conventional switched feedback circuits or the use of additional gain stages. A clamp circuit in parallel with one of the feedback circuits can be used to ensure that the both transimpedance amplifiers operate within their linear regions.

Abstract: A process for determining a quiescent power supply current (I.sub.DDQ) of a device under test (DUT) at a first node. The process includes the steps of providing a reference current to the first node and decoupling a power supply from the first node. A first node voltage is determined at a first time after the power supply is decoupled from the first node. The first node voltage is determined at a second time after the first time. If the first node voltage increases from the first time to the second time, it is indicated that the I.sub.DDQ of the DUT is less than the reference current. If the first node voltage decreases from the first time to the second time, it is indicated that the I.sub.DDQ of the DUT is greater than the reference current.

Abstract: A process for determining a quiescent power supply current (I.sub.DDQ) of a device under test (DUT) at a first node. The process includes the steps of providing a reference current to the first node and decoupling a power supply from the first node. A first node voltage is determined at a first time after the power supply is decoupled from the first node. The first node voltage is determined at a second time after the first time. If the first node voltage increases from the first time to the second time, it is indicated that the I.sub.DDQ of the DUT is less than the reference current. If the first node voltage decreases from the first time to the second time, it is indicated that the I.sub.DDQ of the DUT is greater than the reference current.