ISSN 10637397, Russian Microelectronics, 2011, Vol. 40, No. 7, pp. 446–452. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © V.P. Timoshenkov, 2010, published in Izvestiya Vysshikh Uchebnykh Zavedenii. Elektronika, 2010, No. 4, pp. 20–27.
An increase in the rate of the transmitted informa
tion of the highfrequency and microwave ranges
increases the requirements both for the semiconductor
base and the wire lines of the transmission. As wire
lines, a cable, a microstrip, a coplanar, or a twisted
strip are used. Such a transmission line is a complex
distributed structure with a impedance of 50 or 75
Transmission line has frequency dependent losses. It
means at high frequency losses higher than at low. The
situation is considerably worst if there are passive split
ters (one input
outputs) in the line. In most applied
application, splitters are used, in which
two to four. The target of the equalizer is to compen
sate the losses of the signal line in the range of the
In this study, the principles of the equalization of
the signal are considered, and an integrated circuit
that is optimal in terms of the price/performance is
suggested. An equalizer providing signal compensa
tion in a 50
transmission line is suggested. The 3dB
point bandwidth of the device is 5 GHz and slope of
the amplitude–frequency characteristic is
3.5 dB/GHz in this band. The novelty of the study lies
in original technical solutions providing signal equal
The signal’s passage along the transmission line
with losses (Fig. 1) leads to the loss in the highfre
quency component of the signal. Consequently, any
transmission line has the limitation to transfer signals,
depending on the line length and speed rate. It is pos
sible to solve the problem, on the one hand, by the
development of transmission lines with small losses
(with the disadvantage of a high cost), and on the other
hand, by the development of a device compensating
the losses of the transmission line.
The typical amplitude–frequency (
teristics of a 75
(RG59) and 50
cable are shown in Fig. 2.
In addition to weakening the highfrequency com
ponent, nonlinearity is present in the line. This leads
to the effect of various delays of the frequency compo
nents of the signal. Thus, the variation in the group
delay in the transmission band of the line should not
exceed the duration of the period of the highestfre
quency component of the signal.
The compensation of losses in the transmission line
and group delay for the nonlinear systems is a rather
complex problem. Its theoretical solution of the equal
ization process is to create device which has the
characteristic with shape inversely reflected with
compared to the curves shown in
Fig. 2. By virtue of the considerable nonlinearity of
these curves, for all cases of practical implementation,
the problem has still not been resolved. The situation
An Integrated Equalizer of the Gigahertz Range Based
on Heterojunction Bipolar Transistors
V. P. Timoshenkov
Moscow State Institute of Electronic Technique (Technical University), proezd 4806, 5, Zelenograd, Moscow, 124498 Russia
—The questions of the design of integrated circuits of an equalizer based on heterojunction silicon–
germanium transistors are considered. High speed tuned blocks of the equalizers are a features of the device.
The computer modeling and experimental studies of the devices for signal transfer at a rate of 12.5 Gbit/s are
performed. The experimental results concur well with the results of modeling.
Signal passage along the transmission line.