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refrigeration tools on Thursday, April 15, 2010 4:26:53 AM
A bus circuit of this invention has a bus line. A bus input circuit and
a bus output circuit are connected to the bus line. The bus line is
charged by a precharge circuit. The bus output circuit outputs an
output signal to the bus line by discharging or not discharging
potential of the bus line. The bus input circuit inputs a signal from
the bus line. The
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input circuit includes a feedback circuit which inputs potential of the
bus line as the signal, amplifies the signal in accordance with a
change of the signal, and feeds back the amplified result to the bus
line.
Most of the rules for safety during bus travel are similar to general
ideas for safety overall. But because so much of that experience
entails being second in control (outside of the driver, schedules,
etc.) it is worth the effort to mesh your efforts with theirs for a
successful trip--whether it is long term or a short jaunt across town.
Here are tips.When commuting by bus, use bus stops that are lit well
and not isolated or dangerous. Often bus stations are in a close
proximity to train stations, and some even share waiting rooms and
other amenities. If lighting leaves something to be desired, consider
perching in front of adjoining stores' light, and make a note to report
to the
minibus manufacturer where their lights are burned out or broken.
FIG. 1 is a block diagram showing a bus circuit of the present invention;
FIG. 2 is a block diagram showing a bus circuit according to the second embodiment of the present invention;
FIG. 3 is a circuit diagram showing a bus circuit according to the third embodiment of the present invention;
FIG. 4 is a circuit diagram showing a bus circuit according to the fourth embodiment of the present invention;
FIGS. 5(A) to 5(C) are a circuit diagram of the bus circuit of the
first conventional bus circuit, an operation timing chart and an
input/output characteristic diagram of the hysteresis circuit,
respectively;
FIGS. 6(A) to 6(C) are a circuit diagram of the bus circuit of the
second conventional bus circuit, an operation timing chart and an
input/output characteristic diagram of the comparator used in the
embodiment;
FIG. 7 is a diagram showing the construction of the bus circuit of the third conventional bus circuit; and
FIG. 8 is a diagram showing the construction of the bus circuit of the fourth conventional bus circuit.
The present invention relates to a bus circuit, and more particularly,
to a bus circuit for signal transmission/reception by a plurality of
circuit devices via a common
minibus for sale signal line.
As an example of a conventional bus circuit of this type, Japanese
Patent Application Laid-Open No. Sho 61-58317 discloses two
conventional bus circuits.
Referring to FIGS. 5(A) through 5(C), a first conventional bus circuit
600 has a feedback circuit 610 and bus input/output circuits 671 and
672. The bus circuit 600 is a static-type bus circuit. The feedback
circuit 610 comprises a hysteresis circuit 612 which receives a bus
signal, a buffer 613 which receives an output from the hysteresis
circuit 612, and a transfer gate transistor 614 which receives an
output from the buffer 613. The transfer gate transistor 614 is in an
off state during the first-half cycle of a data transfer period, then
it is in an on state during the last-half cycle of the data transfer
period for transmitting the output from the buffer 613 to a bus signal
line 601.
If the circuit is designed such that the level V1 is lower than a
low-level judgment level V L of the hysteresis circuit 612, a signal,
which is obtained through the hysteresis circuit 612 and the buffer
613, accelerates the discharge potential on the
minibus supplier
signal line 601. When the transfer data signal is at a high level,
high-speed operation is similarly attained by designing the circuit
such that a rising voltage V2 of the bus signal line 601 in the
first-half cycle of the data transfer cycle is higher than a high-level
judgment level V H . In the first conventional bus circuit, since a
feedback circuit is additionally connected to the bus signal line 601,
the hardware in the bus circuit and the amount of load on the bus
signal line increase.
Upon boarding, seek posted instructions of emergency procedures and
exits. Also, commit to memory the number of the bus, and be alert to
your surroundings as well as the people on board. In the event of an
emergency, the two-way radios in buses--or phones owned by drivers--can
contact the base operations.City bus drivers have specific routes, but
in extenuating circumstances, might agree to let you off at an
unscheduled stop. For maximum safety, have someone meet you at your
destination.
MiniBus for sale
stations tend to be a gathering place for homeless people because they
are so often open 'round-the-clock. Be alert for your own safety and
watch your belongings, whether stationary or moving around before
embarking.
In FIGS. 6(a), 6(b) and 6(c), a bus circuit 700 includes a precharge
transistor 702, a feedback circuit 710 and bus input/output circuits
771 and 772. The second conventional bus circuit 700 is a dynamic
(precharge) type bus circuit. The feedback circuit 710 comprises a
comparator 712 which receives a bus signal, a 2-input NOR gate 715, to
which an output from the comparator 712 and a precharge signal T PC are
inputted, and a pull-down transistor 713 which inputs an output from
the 2-input NOR gate 715 as a gate input for pulling down a bus signal
line 701. The feedback circuit 710 is connected to the bus signal line
701.
The bus signal line 701 is charged when the precharge transistor 702 is
turned on by the precharge signal T PC . When low level data is
transferred in the data transfer cycle, the bus signal line 701 is
discharged by discharge transistors 734 and 730 in the
minibus china
input/output circuit 771. When the level of the bus signal line 701
becomes lower than a low-level judgment level V L of the comparator 712
as shown in FIG. 6(c), the pull-down transistor 713 is turned on by the
output of the NOR gate 15. While the feedback circuit 710 accelerates
the discharge from the bus signal line 701, since the feedback circuit
710 is additionally connected to the bus signal line 701, the amount of
hardware of the bus circuit and the load on the bus signal line also
increase.
When alone, try to sit nearer to the driver, and if the bus isn't full,
sit next to an empty seat. Don't make it too apparent that you are
alone, and avoid going anywhere with anyone solo during stops.