PSB2163T-V31TR Infineon Technologies, PSB2163T-V31TR Datasheet - Page 134

• Manufacturer Part Number: PSB2163T-V31TR
• Description: IC AUDIO RINGING CODEC 28-PDSO
• Manufacturer: Infineon Technologies
• Series: ARCOFI®r

Specifications of PSB2163T-V31TR

• Function: CODEC Filter
• Interface: IOM-2, PCI, Serial
• Number Of Circuits: 1
• Voltage - Supply: 5V
• Current - Supply: 900µA
• Power (watts): 1mW
• Operating Temperature: -25°C ~ 80°C
• Mounting Type: Surface Mount
• Package / Case: DSO-28
• Includes: Activation and Deactivation, B-Channel and D-Channel HDLC Controllers, D-Channel Priority Handler, Monitor Channel Handler
• Lead Free Status / RoHS Status: Request inventory verification / Request inventory verification
• Other names: PSB2163T-V31INTR; PSB2163T-V31TR

Transients
To get a satisfying switching performance, experience shows, that losses of the loop
should be kept as low as possible
sufficient and in reality this loss is not perceptible very well, so that a pseudo full-duplex
character can be achieved. In contrast, a switched attenuation larger than 40 dB gives
the feeling of speaking into a hole, like a dead line. In general, it is a fact that the lower
the volume of the speech comes out of the loudspeaker, the lower the inserted
attenuation may be. Of course, to the singing threshold there should always be a certain
reserve to avoid instability and annoying echoes.
For the switching control two speech detectors are necessary, one in the transmit path
and one in the receive branch. Both have to distinguish completely separately between
speech activity and (background) noise. The direction exhibiting a better S/N ratio should
normally be blocked and the path with a poorer S/N ratio should normally be activated.
Thus the path with a higher noise is normally transparent, and hence it will not be
necessary to have a large level difference between noise and speech. On the other
hand, in the path with a better S/N it is not difficult to discriminate between speech bursts
and noise edges.
A volume control must be arranged in such a way that, when turned down, it will reduce
the loss switched in both paths by the same amount. This guarantees that only the
minimum of loss is switched, which yields a comfortable switching feeling.
The sum of build-up and attack times should be very short (around 10 ms), the shorter
the better. The build-up time is the delay associated with the detection of a rising voice
signal, and the attack time (analogous release time) is the switching time required after
having detected speech. The sum of decay time (delay while detecting a decreasing
voice signal) and release time must be relatively long (150 ms)
and does not delay mode switching in a way that it becomes noticeable.
1
2
Semiconductor Group
A. Busla: "Fundamental Considerations in the Design of a Voice-Switched Speakerphone", The
Bell System Technical Journal; Vol. XXXIX, March 1969, Number 2
A. Busla: "Fundamental Considerations in the Design of a Voice-Switched Speakerphone", The
Bell System Technical Journal; Vol. XXXIX, March 1969, Number 2
1)
. Ideally, a loss of about 10 - 20dB should be
133
Speakerphone Implementation
2)
. This prevents clipping