JP2658881B2 - Receive Eb / No detection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reception Eb / No detection circuit, and more particularly, to a reception Eb / No detection circuit for reducing data quality deterioration in a remote sensing data communication line using a carrier-less signal by PCM direct modulation, an inter-satellite communication line and the like. The present invention relates to an apparatus for monitoring by measurement.

[0002]

2. Description of the Related Art A conventional circuit for detecting a reception quality or a reception state includes a reception level detection circuit for extracting a voltage of a signal component, a noise level detection circuit for extracting a noise component, and an S level. And a judgment circuit for judging the quality of / N, and mainly judges the reception quality or the reception state by performing S / N detection.

[0003]

In the phase modulation system based on PCM direct modulation, reception quality is indicated by a ratio of signal energy per bit to noise power density per unit frequency, and it is difficult to evaluate quality only by S / N detection. Met.

Also, by using data such as a PN code and knowing the transmission data in advance, it is possible to measure the data from the demodulated data with a bit error measuring device or the like. It is difficult, and the measurement and evaluation are further complicated by coding and the like, so that evaluation by bit error measurement is difficult.

An object of the present invention is to provide a reception Eb / No detection circuit for appropriately monitoring data quality deterioration in a remote sensing data communication line, an inter-satellite communication line, etc. using a non-carrier signal by PCM direct modulation. is there.

[0006]

The reception Eb / No of the present invention is described.
The detection circuit includes a bandpass filter that extracts an input reception signal, a reception level detection unit having an AGC circuit that obtains a voltage corresponding to the extracted reception level, and a bandpass filter that extracts only thermal noise near the reception signal. A noise level detection unit having a filter and an AGC circuit for obtaining a voltage corresponding to the extracted noise level, and an A / D conversion unit for digitally converting the AGC voltage output from the reception level detection unit and the noise level detection unit, respectively. And a counter section for inputting and counting a reproduction clock reproduced in the receiver and counting the bit rate, a memory section for storing condition data for calculation and correction, and a digital output from the A / D conversion section. Eb / No is calculated using the signal, the bit rate output from the counter unit, and the calculation correction data stored in the memory unit. It is characterized by having a calculation unit.

[0007]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention.

The input of the received signal is connected to the bandpass filter 3, and the output of the bandpass filter 3 is connected to the AGC amplifier 4. The output of the AGC amplifier 4 is an envelope detector 5,
It is connected to a carrier recovery unit and a clock recovery unit (not shown). The output of the envelope detector 5 is a loop filter 6
And the output of the loop filter 6 is connected to the AGC amplifier 4 and the A / D converter 11.

The received signal input is connected to a bandpass filter 7, and the output of the bandpass filter 7 is connected to an AGC amplifier 8. The output of the AGC amplifier 8 is an envelope detector 9
, The output of the envelope detector 9 is connected to the loop filter 10, and the output of the loop filter 10 is
It is connected to the amplifier 8 and the A / D converter 11.

Further, an output of a clock reproducing unit (not shown) is connected to a counter unit 13, and the counter unit 13, A / A
The D conversion unit 11 and the memory unit 14 are
2 are connected.

The AGC amplifier 4, the envelope detector 5 and the loop filter 6 constitute an AGC circuit, and the AGC circuit and the bandpass filter 3 constitute a reception level detector 1. The AGC amplifier 8, the envelope detector 9, and the loop filter 10 constitute an AGC circuit, and the AGC circuit and the bandpass filter 7 constitute a noise level detection unit 2.

Next, the operation of this embodiment will be described.

The input received signal is distributed to each of a reception level detection unit 1 and a noise level detection unit 2. In the reception level detector 1, the bandpass filter 3 improves the S / N of the input signal, and the AGC circuit including the AGC amplifier 4, the envelope detector 5, and the loop filter 6 controls the reception level. A considerable AGC voltage is obtained. AGC voltage is LOG in order to improve calculation accuracy.
-Perform LINEAR conversion.

In the noise level detector 2, only the thermal noise near the signal is extracted by the bandpass filter 7, and the noise is detected by the AGC circuit composed of the AGC amplifier 8, the envelope detector 9 and the loop filter 10. Obtain the voltage according to the level. FIG. 2 is a diagram illustrating a frequency relationship between the bandpass filters 3 and 7.

The A / D converter 11 includes a reception level detector 1
Then, the detection voltage output from the noise level detection unit 2 is converted into a digital value and sent to the calculation unit 12.

The counter unit 13 measures the bit rate by inputting a reproduction clock reproduced in the receiver main body, and sends the result to the calculation unit 12.

In the operation unit 12, the A / D conversion unit 1
1. C / No, Eb / N using the data of the counter unit 13 and the calculated correction data stored in the memory unit 14.
o is calculated and the result is output to the outside.

[0018]

As described above, according to the present invention, Eb / No can be detected by adding a bit rate detection function, and the data quality of a received signal can be monitored without detecting a bit error rate. It has the effect of being able to do it. In particular, it is effective for a bit rate tunable receiver.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing a frequency relationship of the bandpass filter shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 reception level detection unit 2 noise level detection unit 3, 7 bandpass filter 4, 8 AGC amplifier 5, 9 envelope detector 6, 10 loop filter 11 A / D conversion unit 12 operation unit 13 counter unit 14 memory unit

Claims (3)

(57) [Claims] 1. A band filter for extracting an input reception signal, a reception level detection unit having an AGC circuit for obtaining a voltage corresponding to the extracted reception level, and a band for extracting only thermal noise near the reception signal. Filter and AGC for obtaining voltage according to extracted noise level
A noise level detection unit having a circuit; an A / D conversion unit for digitally converting the AGC voltage output from the reception level detection unit and the noise level detection unit; A memory for storing condition data for calculation and correction; a digital signal output from the A / D converter; a bit rate output from the counter; And a calculation unit for calculating Eb / No using the calculation correction data stored in the reception Eb / No. 2. The AGC circuit comprises an AGC amplifier, an envelope detector, and a loop filter, an output of the AGC amplifier is connected to the envelope detector, and an output of the envelope detector is a loop filter. 2. The reception Eb / No detection circuit according to claim 1, wherein an output of the loop filter is connected to the AGC amplifier and the A / D converter. 3. The reception Eb / No according to claim 1, wherein the reception Eb / No is used for an apparatus for monitoring data quality deterioration of a remote sensing data communication line and an inter-satellite communication line using a carrier-free signal by PCM direct modulation. Detection circuit.