Error detection/correction and fault detection/recovery – Pulse or data error handling – Error count or rate
Utility Patent
1998-11-24
2001-01-02
Chung, Phung M. (Department: 2784)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Error count or rate
C714S738000, C714S744000
Utility Patent
active
06170069
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a bit error measuring device for a modem device and a bit error measuring method for the same, which can detect a flow control code outputted from a modem device connected with a data processing device through a connector, for example, an RS-232-C connector standardized by Electronic Industries Association, and which can control a transmission of a test pattern and can mask the flow control code, when a bit error measurement is carried out.
2. Description of the Related Art
FIG. 4
shows a construction of a typical bit error measuring device for a modem device, which is connected with a data processing device, such as a personal computer, through an RS-232-C connector. The construction of the bit error measuring device will be explained. In
FIG. 4
, the bit error measuring device comprises a bit error measuring circuit
21
, a test pattern transmitting circuit
22
and a clock controlling circuit
23
.
The bit error measuring circuit
21
measures (or detects) a bit error in an input signal
21
A outputted from a modem device (not shown in the figure), which is a pseudo-random pattern recommended by International Telecommunications Union-Telecommunication (hereinafter, referred as to ITU-T). The test pattern transmitting circuit
22
outputs a test pattern signal
22
A which is a random code recommended by ITU-T, to the outside of the bit error measuring device by synchronizing it with a test pattern synchronizing clock signal
23
A outputted from the clock controlling circuit
23
. As shown in
FIG. 5
, the clock controlling circuit
23
divides a basic clock signal by using a dividing circuit
25
and generates the test pattern synchronizing clock signal
23
A to output it to the test pattern transmitting circuit
22
.
According to the bit error measuring device as shown in
FIG. 4
, the test pattern transmitting circuit
22
outputs a test pattern signal
22
A to the outside of the bit error measuring device by synchronizing it with a test pattern synchronizing clock signal
23
A outputted from the clock controlling circuit
23
. However, because a flow control code outputted from a modem device cannot be detected, there is a problem that a control of stopping or retransmitting the test pattern signal cannot be carried out in accordance with the flow control code.
SUMMARY OF THE INVENTION
The present invention was developed in view of these problems.
An object of the present invention is to provide a bit error measuring device for a modem device or a bit error measuring method for the same, which can detect a flow control code outputted from the modem device, for example, a D3 code (a test patternstopping requestcode), a D1 code (a test pattern transmitting request code) or the like, and which can control a transmission of a test pattern and can mask the flow control code, when a bit error measurement is carried out.
That is, in accordance with one aspect of the present invention, the bit error measuring device for modem device, for measuring bit errors when a flow control operation is carried out, comprises;
a control code detecting unit for outputting a control code detecting signal by detecting a flow control code set in an input signal inputted thereinto from the modem device, and for masking the flow control code set in the input signal and outputting the input signal of which the flow control code is masked,
a bit error measuring unit for measuring bit errors in the input signal of which the flow control code is masked,
a clock controlling unit for outputting a test pattern synchronizing clock signal to a test pattern transmitting unit,
the test pattern transmitting unit for transmitting a test pattern signal when the flow control operation is carried out by the modem device, and
a stop bit detecting unit for outputting a stop bit detecting signal by detecting a stop bit in the test pattern signal transmitted by the test pattern transmitting unit,
wherein the test pattern synchronizing clock signal controls a transmission/stop operation of the test pattern signal on the basis of the stop bit detecting signal outputted from the stop bit detecting unit and the control code detecting signal outputted from the control code detecting unit.
According to the above-described bit error measuring device, the control code detecting unit outputs a control code detecting signal by detecting a flow control code set in an input signal inputted thereinto from the modem device, masks the flow control code set in the input signal, and outputs the input signal of which the flow control code is masked. The bit error measuring unit measures bit errors in the input signal of which the flow control code is masked. The clock controlling unit outputs a test pattern synchronizing clock signal for controlling a transmission/stop operation of the test pattern signal on the basis of the stop bit detecting signal outputted from the stop bit detecting unit and the control code detecting signal outputted from the control code detecting unit. The test pattern transmitting unit transmits a test pattern signal when the flow control operation is carried out by the modem device. The stop bit detecting unit outputs a stop bit detecting signal by detecting a stop bit in the test pattern signal transmitted by the test pattern transmitting unit.
Thereby, error bits are not transmitted to the units to which the test pattern signal is transmitted. Further, the test pattern signal can be stopped in accordance with the state of the stop bit, and can be transmitted by synchronizing with the synchronizing clock. The bit error measuring unit can avoid judging that the flow control codes are bit errors, and the bit error measuring device for a modem device, which can carry out the flow control can be provided. As a result, the present invention can provide a high performance and high reliability bit error measuring device.
The clock controlling unit may comprise;
a start judging unit for outputting a start bit judging signal by judging that a start bit is detected in the control code detecting signal outputted from the control code detecting unit on the basis of a basic clock signal for setting a timing of each transmission/stop operation of the test pattern signal, and
a stop judging unit for stopping the test pattern transmitting unit from transmitting the test pattern signal on the basis of the stop bit detecting signal outputted from the stop bit detecting unit and the control code detecting signal outputted from the control code detecting unit, and for controlling the test pattern synchronizing clock signal so as to retransmit the test pattern signal by the test pattern transmitting unit on the basis of the start judging signal outputted from the start judging unit.
In accordance with another aspect of the present invention, the bit error measuring device for modem method, for measuring bit errors when a flow control operation is carried out, comprises the steps of;
outputting a control code detecting signal by detecting a flow control code set in an input signal inputted from the modem device, masking the flow control code set in the input signal and outputting the input signal of which the flow control code is masked,
measuring bit errors in the input signal of which the flow control code is masked,
controlling a transmission/stop operation of a test pattern signal by generating a test pattern synchronizing clock signal on the basis of a stop bit detecting signal and the control code detecting signal,
transmitting the test pattern signal when the flow control operation is carried out by the modem device, and
generating the stop bit detecting signal by detecting a stop bit in the test pattern signal.
According to the above-described bit error measuring method, a control code detecting signal is outputted by detecting a flow control code set in an input signal inputted from the modem device. A flow control code set in the input signal is masked. An input signal of which the flow control code is masked, is outputted. The bit
Ohtani Morito
Suzuki Takao
Ando Electric Co. Ltd.
Chung Phung M.
Pillsbury Madison & Sutro LLP
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