Browse Prior Art Database

Accurate Measurement of Propagation Velocity in a Module

IP.com Disclosure Number: IPCOM000039562D
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Bhatia, HS: AUTHOR [+3]

Abstract

A new measurement technique has been proposed for determining the propagation time of electrical signals in semiconductor modules. The method will serve to minimize errors attendant with other techniques. Propagation time covers only a range of a few picoseconds and may be measured by injecting an external high frequency signal into one end of a module line and then noting the phase shift as it emerges at the other end. It is necessary to connect the two ends of the line to the external source through a set of pads and probes. This may introduce errors in the measurement because of the associated discontinuities and loading effects. In the proposed method a very high frequency sinusoidal signal is generated on a special test chip which is mounted on the module in a normal manner, as shown in the drawing.

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Accurate Measurement of Propagation Velocity in a Module

A new measurement technique has been proposed for determining the propagation time of electrical signals in semiconductor modules. The method will serve to minimize errors attendant with other techniques. Propagation time covers only a range of a few picoseconds and may be measured by injecting an external high frequency signal into one end of a module line and then noting the phase shift as it emerges at the other end. It is necessary to connect the two ends of the line to the external source through a set of pads and probes. This may introduce errors in the measurement because of the associated discontinuities and loading effects. In the proposed method a very high frequency sinusoidal signal is generated on a special test chip which is mounted on the module in a normal manner, as shown in the drawing. The signal is split into two parts in the variable frequency oscillator (VFO) whose frequency is controlled by an external DC control line. One output is fed to a built-in chain of binary dividers so as to reduce the frequency to a conveniently low value before it is taken out of the chip for measurement by an external frequency meter. The second output of the VFO is fed to an off-chip driver which drives two module lines L1, which has a short loop, and L2, which has a long loop. The two lines terminate in the inputs IN1 and IN2 of the built-in linear mixer whose output is amplified and detected on the chip...