Apparatus for providing two-way communication in underground facilities
First Claim
Patent Images
1. A receiver apparatus for receiving information in an underground facility comprising:
- an antenna means for receiving a digitally frequency shift keyed modulated electromagnetic carrier signal at a frequency in the range 0.1-2 MHz and having a sequence of high modulation frequency time intervals and low modulation frequency time intervals and generating a received signal;
a selective receiver means for receiving the received signal from the antenna means and selecting predetermined frequency components of the received signal and rejecting other frequency components of the received signal so as to produce a first IF signal having the digitally modulation of the digitally electromagnetic carrier signal, said selective receiver means including a frequency tuning means for tuning the selective receiver means, a frequency display means for providing a display of frequency to which the selective receiver means is tuned, and a signal strength meter for providing a display of strength of the received signal;
a frequency shift keying detector for demodulating the first IF signal and producing a digital signal as a series of 1'"'"'s and 0'"'"'s according to the respective high modulation frequency time intervals and low modulation frequency time intervals of the first IF signal;
a digital-to-analog converter for converting the digital signal to analog form according to a predetermined decoding algorithm and producing an analog electrical signal; and
an audio generator for receiving the analog electrical signal and producing an acoustic signal representative of the analog electrical signal.
0 Assignments
0 Petitions
Accused Products
Abstract
The invention relates to an apparatus which is desiged for underground use in order to facilitate a two-way communication. The apparatus is operated within the frequency band 0.1-2 MHz, in order to make the electromagnetic waves propagate advantageously by utilizing the metal structures installed in the underground facilities and the bedrock itself. According to the invention, the transmitter/receiver unit is provided with an analog to digital converter (5) and respectively a digital to analog converter (20) in order to transmit the intermediate signal coded in digital form in between the two units of the apparatus.
-
Citations
12 Claims
-
1. A receiver apparatus for receiving information in an underground facility comprising:
-
an antenna means for receiving a digitally frequency shift keyed modulated electromagnetic carrier signal at a frequency in the range 0.1-2 MHz and having a sequence of high modulation frequency time intervals and low modulation frequency time intervals and generating a received signal; a selective receiver means for receiving the received signal from the antenna means and selecting predetermined frequency components of the received signal and rejecting other frequency components of the received signal so as to produce a first IF signal having the digitally modulation of the digitally electromagnetic carrier signal, said selective receiver means including a frequency tuning means for tuning the selective receiver means, a frequency display means for providing a display of frequency to which the selective receiver means is tuned, and a signal strength meter for providing a display of strength of the received signal; a frequency shift keying detector for demodulating the first IF signal and producing a digital signal as a series of 1'"'"'s and 0'"'"'s according to the respective high modulation frequency time intervals and low modulation frequency time intervals of the first IF signal; a digital-to-analog converter for converting the digital signal to analog form according to a predetermined decoding algorithm and producing an analog electrical signal; and an audio generator for receiving the analog electrical signal and producing an acoustic signal representative of the analog electrical signal. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A transceiver apparatus for providing two-way information communication in an underground facility, comprising:
-
a transmitter device having an audio input for receiving an input signal containing primary information, a filter means for filtering the input signal and producing a primary signal having only those frequency components necessary for communicating said primary information, an analog-to-digital converter for converting the primary signal into a digital signal according to a predetermined coding algorithm, and a modulator for producing a modulated carrier signal by using said digital signal and a predetermined modulation format to modulate a carrier signal having a frequency in the range from 0.1-2 MHz; an antenna network having an antenna, said antenna network being operable selectively either for receiving the modulated carrier signal from the transmitter device and propagating the modulated carrier signal in electromagnetic form, or for receiving a modulated electromagnetic carrier signal having a frequency in the range from 0.1 to 2 MHz and generating a received signal; and a receiver device having a receiver input for receiving the received signal, a selective receiver means for removing frequency components outside a predetermined spectral range from the received signal for producing an IF signal having the modulation that was present on the modulated electromagnetic signal, a detector for demodulating the IF signal according to the inverse of said predetermined modulation format to produce a received digital signal, a digital-to-analog converter for producing a decoded digital signal by decoding the received digital signal according to the inverse of said predetermined coding algorithm, and an audio generator for producing an analog output signal representative of the decoded digital signal, said selective receiver means including a frequency tuning means for tuning the selective receiver means, a frequency display means for providing a display of frequency to which the selective receiver means is tuned, and a signal strength meter for providing a display of strength of the received signal. - View Dependent Claims (7, 8, 9, 10, 11, 12)
-
Specification