摘要:
In a multi-layer substrate module receiving from an external earth node (20) supply of a reference potential (Vss) for grounding, a plurality of ground lines (170-1, 170-2, 170-3) are provided respectively corresponding to a plurality of internal circuits (210, 220, 230). Moreover, a common node (Ncmn) for coupling the ground lines (170-1, 170-2, 170-3) is provided in an insulating layer (105C) of the multi-layer substrate module. The common node (Ncmn) is electrically coupled to the earth node 20 through a ground pin terminal 204 shared by the plurality of internal circuits (210, 220, 230). Preferably, the common node (Ncmn) is provided in the lowest insulating layer of the multi-layer substrate module. Thus, parasitic inductance of the portion through which an earth current flows, that is, the portion common to the plurality of internal circuits (210, 220, 230), can be suppressed with a small number of ground pin terminals. Accordingly, the inflow phenomenon of the earth current between the plurality of internal circuits (210, 220, 230) is prevented, enabling stable operation.
摘要:
In a multi-layer substrate module receiving from an external earth node supply of a reference potential for grounding, a plurality of ground lines are provided respectively corresponding to a plurality of internal circuits. Moreover, a common node for coupling the ground lines is provided in an insulating layer of the multi-layer substrate module. The common node is electrically coupled to the earth node through a ground pin terminal shared by the plurality of internal circuits. Preferably, the common node is provided in the lowest insulating layer of the multi-layer substrate module. Thus, parasitic inductance of the portion through which an earth current flows, that is, the portion common to the plurality of internal circuits, can be suppressed with a small number of ground pin terminals. Accordingly, the inflow phenomenon of the earth current between the plurality of internal circuits is prevented, enabling stable operation.
摘要:
In a cellular telephone provided with a receiving circuit of a direct conversion type, a passive low-pass filter is arranged between a mixer for an I-channel and a base band circuit for removing interference waves of or above a channel next to a channel neighboring to the I-channel, and another passive low-pass filter is arranged between a mixer for a Q-channel and the base band circuit for removing interference waves of or above a channel next to a channel neighboring to the Q-channel. Since the low-pass filters for removing the interference waves of or above the channel next to the neighboring channel are of a differential type, the circuit scale can be small, and the power consumption is small. Since the interference waves are removed by the passive low-pass filters and the active low-pass filters, only the desired channel can be reliably received.
摘要:
In a cellular telephone having a receiving circuit of a direct conversion type using an even harmonic orthogonal mixer, high-pass filters for removing a DC offset component are arranged before and after a variable gain amplifier in a base band circuit. The DC offset component occurred in the even harmonic orthogonal mixer is always constant, and the DC offset component occurred in the variable gain amplifier frequently varies so that a cutoff frequency of the front high-pass filter is set to be lower than a cutoff frequency of the rear high-pass filter, and the frequencies are set to achieve a fast transition response.
摘要:
At the onset of an operation, a level of a base band signal at an input side of a variable gain amplifying circuit is detected by a logarithmic amplifier having a wide dynamic range, and, a control unit controls a gain of a low-noise amplifier in a previous step of a low-pass filter based on the detected level and also controls a gain of variable gain amplifier, whereby saturation at an analog base band portion is prevented even when the level of the input signal is high.
摘要:
A wireless terminal device includes a transmitting circuit, an isolator, a band pass filter, a switch, a transmitting antenna, a receiving circuit, a band pass filter, a switch, a receiving antenna, a high-pass filter, a low-pass filter and an input/output port. A transmission wave of a frequency is conveyed from the transmitting circuit to the input/output port via the isolator, the band pass filter and the low pass filter, and further to a vehicle antenna. Here, the transmission wave in the direction towards the receiving circuit is blocked by the high-pass filter. On the other hand, a reception wave of a frequency is conveyed from the vehicle antenna to the input/output port, and to the receiving circuit via the high-pass filter and the band pass filter. Here, the reception wave in the direction towards the transmitting circuit is blocked by the low-pass filter. Thus, transmission and reception can simultaneously be performed via a single input/output port, so that the wireless terminal device of the invention is compatible with a general wireless terminal device which performs simultaneous transmission/reception by one transmitting/receiving share antenna.
摘要:
A level of a base band signal at an input side of a variable gain amplification circuit is detected by a logarithmic amplifier having a wide input voltage range at a start of an operation, a control unit then performs a coarse feedforward control on a gain of the variable gain amplifier based on the detected level and finds a level of an output of an A/D converter by a mean square deriving circuit and inputs the resulting signal to the control unit. Then the control unit performs a fine feedback control on the variable gain amplifier based on the detected level.
摘要:
A level of a base band signal at an input side of a variable gain amplification circuit is detected by a logarithmic amplifier having a wide input voltage range at a start of an operation, a control unit then performs a coarse feedforward control on a gain of the variable gain amplifier based on the detected level and finds a level of an output of an A/D converter by a mean square deriving circuit and inputs the resulting signal to the control unit. Then the control unit performs a fine feedback control on the variable gain amplifier based on the detected level.
摘要:
A mobile phone includes a lower housing having one end and the other end, an upper housing having one end pivotally connected to the lower housing, and an antenna accommodated close to one end of the lower housing. The other end of the upper housing pivots toward and away from the other end of the lower housing. The mobile phone is used in close proximity to a user's head with the other end of the upper housing being distanced from the other end of the lower housing. Upon use, the lower housing is disposed relative to the upper housing so that the upper housing intervenes between the antenna and the user's head.
摘要:
A PDA use antenna device comprising a first antenna for use in a first use configuration, a second antenna for use in a second use condition, a control part which discriminates between said first use condition and said second use condition and outputs a discrimination signal and a antenna selection device which selects which one of said first antenna and said second antenna should be used on the basis of the discrimination signal of said control part and connects the selected antenna to the wireless circuit. By selecting and using the optimal antenna for each use condition, use conditions can be easily discriminated. Moreover improved and stable antenna reliability can be ensured irrespective of use condition.