Digital circuit multiplication equipment

• US 7,065,099 B1
• Filed: 09/19/2000
• Issued: 06/20/2006
• Est. Priority Date: 02/08/2000
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Suzuki, Shigeaki, Fushimi, Wataru, Yajima, Hisashi
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): Moore, Ian N.
• Application Number:
  US09/664,096
• Time in Patent Office: 2,100 Days
• Field of Search: 370/465, 370/535, 370/537, 370/540, 704/208, 704/210, 704/212, 704/215
• US Class Current: 370/465
• CPC Class Codes: H04J 3/12 Arrangements providing for calling or supervisory signals
• CPC Class Codes: H04J 3/1688 the demands of the users being taken into account after redundancy removal, e.g. by predictive coding, by variable sampling reducing bandwidth of signals in general H04B1/66; in PCM-systems H04B14/046; removal of redundancy in telegraph communication H03M7/30
• CPC Class Codes: H04J 3/17 in which the transmission channel allotted to a first user may be taken away and re-allotted to a second user if the first user becomes inactive, e.g. TASI speech analysis or identification G10L

Abstract

In a digital circuit multiplication equipment (DCME) equipped with tandem pass-through function, a speech coding device and a speech decoding device are resettable in a synchronous resetting mode. The DCME includes a transmission device and a unit to continuously assign and transmit data from a trunk channel to another DCME via a bearer circuit and an exchange during pass-through operation.

Claims

1. In a digital circuit multiplication equipment equipped with a tandem pass-through function capable of pass-through transmitting a signal, using a trunk channel, connected via an exchange to another digital circuit multiplication equipment,

the digital circuit multiplication equipment comprising:

means for transmitting number of a trunk channel operated under pass-through operation to the another digital circuit multiplication equipment connected via a bearer circuit;

means for continuously assigning the bearer circuit with respect to the trunk channel operated under pass-through operation;

means for embedding information indicative of a encoding rate of a encoded speech signal from the bearer circuit into the signal which is outputted with respect to the trunk channel operated under pass-through operation;

means for detecting the information indicative of said encoding rate from an input signal of the trunk channel operated under pass-through operation;

means for determining an assignment of said trunk channel to the bearer circuit by using said encoding rate detected from the input signal of the trunk channel operated under pass-through operation; and

means for delaying the encoded speech signal contained in the input signal of the trunk channel in such a case that when the encoding rate of the encoded speech signal contained in the input signal of the trunk channel operated under pass-through operation is transmitted, the assignment rate change of said trunk channel to the bearer circuit is delayed, and for starting to output the delayed encoded speech signal after the bearer circuit has been assigned.

2. A digital circuit multiplication equipment as claimed in claim 1, wherein:

said digital circuit multiplication equipment is further comprised of;

means for outputting a second invalid encoded signal to the bearer circuit until the assignment rate to the bearer circuit is changed, said second invalid encoded signal indicating that said invalid encoded signal is an invalid encoded speech signal, in such a case that when the encoding rate of the encoded speech signal contained in the input signal of the trunk channel operated under pass-through operation is transmitted, the assignment rate change of said trunk channel to the bearer circuit is delayed;

a speech-decoding device for outputting only a signal different from both a first invalid encoded signal and said second invalid encoded signal; and

means for outputting a silent PCM signal in the case that said first invalid encoded signal is entered from the bearer circuit, and also for outputting a prediction PCM signal for predicting a PCM signal which should be subsequently outputted in such a case that said second invalid encoded signal is inputted.

3. A digital circuit multiplication equipment as claimed in claim 2, wherein:

when a speech encoding system corresponds to the ADPCM system defined in the ITU-T recommendation G.726, and wherein a encoded speech signal which is not defined by said ITU-T recommendation and contains such encodes, all of which for 1 sample are equal to “

1”

, is used as said second invalid encoded signal.

4. A digital circuit multiplication equipment as claimed in claim 2, wherein:

when a speech encoding system corresponds to the CELP system, and wherein a encoded speech signal containing a vector is used as said second invalid encoded signal, the use frequency of which vector being low when a speech signal is inputted into the encoding device.

5. In a digital circuit multiplication equipment equipped with a tandem pass-through function capable of pass-through transmitting a signal, using a trunk channel, connected via an exchange to another digital circuit multiplication equipment, the digital circuit multiplication equipment comprising:

means for embedding information into the signal which is outputted using the trunk channel under pass-through operation, said information indicating as to whether or not a encoded speech signal derived from a bearer circuit is present;

means for detecting from an input signal of the trunk channel operated under pass-through operation, information indicating as to whether or not said encoded speech signal derived from said bearer circuit is present;

means for outputting a first invalid encoded signal indicative of being equal to an invalid encoded signal with respect to the bearer circuit in such a case that the encoded speech signal derived from the bearer circuit is not contained in the input signal of the trunk channel operated under the pass-through operation;

a speech decoding device for outputting only a signal different from said first invalid encoded signal;

means for outputting a silent PCM signal in the trunk channel which receives said first invalid encoded signal from the bearer circuits;

means for determining an assignment of the trunk channel operated under pass-through operation to the bearer circuit by employing such information for indicating as to whether or not the encoded speech signal derived from the bearer circuit is present in the input signal of the trunk channel; and

means for delaying the encoded signal contained in the input signal of the trunk channel in such a case that when a state under which the encoded speech signal is not present from the bearer circuit contained in the input signal of the trunk channel operated under pass-through operation is transmitted to another state under which the encoded speech signal is present, the assignment of said trunk channel to the bearer circuit is delayed, and for starting to output said delayed encoded signal after the trunk channel has been assigned to the bearer circuit.

6. In a digital circuit multiplication equipment equipped with a tandem pass-through function capable of pass-through transmitting a signal, using a trunk channel, connected via an exchange to another digital circuit multiplication equipment, the digital circuit multiplication equipment comprising:

means for embedding information into the signal which is outputted using the trunk channel under pass-through operation, said information indicating as to whether or not a encoded speech signal derived from a bearer circuit is present;

means for detecting from an input signal of the trunk channel operated under pass-through operation, information indicating as to whether or not said encoded speech signal derived from said bearer circuit is present;

means for outputting a first invalid encoded signal indicative of being equal to an invalid encoded signal with respect to the bearer circuit in such a case that the encoded speech signal derived from the bearer circuit is not contained in the input signal of the trunk channel operated under the pass-through operation;

a speech decoding device for outputting only a signal different from said first invalid encoded signal;

means for outputting a silent PCM signal in the trunk channel which receives said first invalid encoded signal from the bearer circuit;

means for outputting encoded speech signals which correspond to plural frames and have been inputted from the bearer circuit in the past with respect to the trunk channel operated under pass-through operation;

means for extracting said encoded speech signal corresponding to the plural frames from the input signal of the trunk channel operated under pass-through operation; and

means for outputting old encoded speech signals by the delayed assignment number from the encoded speech signals corresponding to the plural frames, which are extracted from the input signal of said trunk channel in such a case that when a state under which the encoded speech signal is not present from the bearer circuit contained in the input signal of the trunk channel operated under pass-through operation is transmitted to another state under which the encoded speech signal is present, the assignment of said trunk channel to the bearer circuit is delayed, and for starting to output a delayed encoded speech signal after the trunk channel has been assigned to the bearer circuit.

7. In a digital circuit multiplication equipment equipped with a tandem pass-through function capable of pass-through transmitting a signal, using a trunk channel, connected via an exchange to another digital circuit multiplication equipment, the digital circuit multiplication equipment comprising:

means for embedding information into the signal which is outputted using the trunk channel under pass-through operation, said information indicating as to whether or not a encoded speech signal derived from a bearer circuit is present;

means for detecting from an input signal of the trunk channel operated under pass-through operation, information indicating as to whether or not said encoded speech signal derived from said bearer circuit is present;

means for outputting a first invalid encoded signal indicative of being equal to an invalid encoded signal with respect to the bearer circuit in such a case that the encoded speech signal derived from the bearer circuit is not contained in the input signal of the trunk channel operated under the pass-through operation;

a speech decoding device for outputting only a signal different from said first invalid encoded signal;

means for outputting a silent PCM signal in the trunk channel which receives said first invalid encoded signal from the bearer circuit;

means for embedding information indicative of a encoding rate of a encoded speech signal from the bearer circuit into the signal which is outputted with respect to the trunk channel operated under pass-through operation;

means for detecting the information indicative of said encoding rate from the input signal of the trunk channel operated under pass-through operation;

means for determining an assignment of said trunk channel to the bearer circuit by using said encoding rate detected from the input signal of the trunk channel operated under pass-through operation;

means for delaying the encoded speech signal contained in the input signal of the trunk channel in such a case that when the encoding rate of the encoded speech signal contained in the input signal of the trunk channel operated under pass-through operation, is transmitted from a high rate to a low rate, the assignment rate change of said trunk channel to the bearer circuit is delayed, and for starting to output the delayed encoded speech signal after the bearer circuit has been assigned,

means for outputting a second invalid encoded signal to the bearer circuit until the assignment rate to the bearer circuit is changed, said second invalid encoded signal indicating that said second invalid encoded signal is an invalid encoded speech signal, in such a case that when the encoding rate of the encoded speech signal contained in the input signal of the trunk channel operated under pass-through operation is transmitted from the high rate to the low rate, the assignment rate change of said trunk channel to the bearer circuit is delayed;

means for synthesizing the encoded speech signal contained in the input signal of said trunk channel with such information for indicating such a fact that the encoded speech signal of the low encoding rate is contained in the case that when the encoding rate of the encoded speech signal contained in the input signal of the trunk channel operated under pass-through operation, the assignment rate change of said trunk channel to the bearer circuit is delayed, and then for outputting the synthesized encoded speech signal to the bearer circuit;

a speech decoding device for outputting only such a signal different from both said first invalid encoded signal and said second invalid encoded signal; and

means for outputting a silent PCM signal in the case that said first invalid encoded signal is entered from the bearer circuit, and for outputting a prediction PCM signal for predicting a PCM signal which would be subsequently outputted in such a case that said second invalid encoded signal is inputted; and

further for extracting the encoded signal of the low rate to be decoded into the PCM signal in the input case that such a signal is inputted in which said encoded signal of the low rate is synthesized with the information for indicating that the encoded signal of the low rate is contained.

8. In a digital circuit multiplication equipment equipped with a tandem pass-through function capable of pass-through transmitting a signal, using a trunk channel, connected via an exchange to another digital circuit multiplication equipment,

the digital circuit multiplication equipment comprising:

means for embedding information into the signal which is outputted using the trunk channel under pass-through operation, said information indicating as to whether or not a encoded speech signal derived from a bearer circuit is present;

means for detecting from an input signal of the trunk channel operated under pass-through operation, information indicating as to whether or not said encoded speech signal derived from said bearer circuit is present;

means for outputting a first invalid encoded signal indicative of being equal to an invalid encoded signal with respect to the bearer circuit in such a case that the encoded speech signal derived from the bearer circuit is not contained in the input signal of the trunk channel operated under the pass-through operation;

a speech decoding device for outputting only a signal different from said first invalid encoded signal;

means for outputting a silent PCM signal in the trunk channel which receives said first invalid encoded signal from the bearer circuit;

wherein when a speech encoding system corresponds to the ADPCM system defined in the ITU-T recommendation G.726, and wherein a encoded speech signal which is not defined by said ITU-T recommendation and contains such encodes, all of which for 1 sample are equal to “

1”

, is used as said first invalid encoded signal.

9. In a digital circuit multiplication equipment equipped with a tandem pass-through function capable of pass-through transmitting a signal, using a trunk channel, connected via an exchange to another digital circuit multiplication equipment, the digital circuit multiplication equipment comprising:

means for embedding information into the signal which is outputted using the trunk channel under pass-through operation, said information indicating as to whether or not a encoded speech signal derived from a bearer circuit is present;

means for detecting from an input signal of the trunk channel operated under pass-through operation, information indicating as to whether or not said encoded speech signal derived from said bearer circuit is present;

means for outputting a first invalid encoded signal indicative of being equal to an invalid encoded signal with respect to the bearer circuit in such a case that the encoded speech signal derived from the bearer circuit is not contained in the input signal of the trunk channel operated under the pass-through operation;

a speech decoding device for outputting only a signal different from said first invalid encoded signal;

means for outputting a silent PCM signal in the trunk channel which receives said first invalid encoded signal from the bearer circuit;

wherein, when a speech encoding system corresponds to the CELP system, a encoded speech signal containing a vector is used as said first invalid encoded signal, the use frequency of which vector being low when a speech signal is inputted into the encoding device.