- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄382825 > 75T2091 (TDK Corporation) DTMF Transceivers PDF資料下載
參數(shù)資料
| 型號(hào)： | 75T2091 |
| 廠商： | TDK Corporation |
| 英文描述： | DTMF Transceivers |
| 中文描述： | 雙音多頻收發(fā)器 |
| 文件頁(yè)數(shù)： | 2/9頁(yè) |
| 文件大小： | 75K |
| 代理商： | 75T2091 |
75T2089/2090/2091
DTMF Transceivers
2
DESCRIPTION
(continued)
The 75T2091 also incorporates an early detect
function which is useful in multi-channel radio
scanning
applications.
components necessary for the 75T2089/2090/2091
are a 3.58 MHz “colorburst” crystal with a parallel 1
M
resistor. This provides the time base for digital
functions and switched-capacitor filters in the device.
No external filtering is required.
The
only
external
CIRCUIT OPERATION
RECEIVER
The DTMF Receiver in the 75T2089/2090/2091 detects
the presence of a valid tone pair (indicating a single
dialed digit) on a telephone line or other transmission
medium. The analog input is pre-processed by 60 Hz
reject and band-splitting filters, then hard-limited to
provide Automatic Gain Control. Eight bandpass filters
detect the individual tones. The digital post-processor
times the tone durations and provides the correctly
coded digital outputs. The outputs will drive standard
CMOS circuitry, and are three-state enabled to facilitate
bus-oriented architectures.
DIN
This pin accepts the analog input. It is internally
biased so that the input signal may be AC coupled.
The input may be DC coupled as long as it does not
exceed the positive supply. Proper input coupling is
illustrated in Figure 1.
The IC is designed to accept sinusoidal input
waveforms but will operate satisfactorily with any
input that has the correct fundamental frequency
with harmonics greater than -20 dB below the
fundamental.
CRYSTAL OSCILLATOR
The IC contains an onboard inverter with sufficient
gain to provide oscillation when connected to a low-
cost television “colorburst” crystal. The crystal is
placed between XIN and XOUT in parallel with a
1M
z
resistor, while XEN is tied high. Since the
switched-capacitor-filter time base is derived from
the crystal oscillator, the frequency accuracy of all
portions of the IC depends on the time base
tolerance. The DTMF Receiver frequency response
and timing is specified for a time base accuracy of at
least
=
0.005%. ATB is a clock output with the
frequency of 1/8 of crystal. Other devices may use
the same frequency reference by tying their ATB
pins to the ATB of a crystal connected device. XIN
and XEN of the auxiliary devices must then be tied
high and low respectively, XOUT is left floating.
XOUT is designed to drive a resonant circuit only
and is not intended to drive additional devices. Ten
devices may run off a single crystal-connected
transceiver as shown in Figure 2.
Vp
VIN<VP
DIN
GND
10 pF
>100 k
(
Vp
VIN>VP
DIN
GND
10 pF
>100 k
(
0.01 μF
8
8
FIGURE 1: Input Coupling
75T20XX
XIN
XEN
XEN
ATB
ATB
XOUT
XIN Connected to VP
VP
Up to 10 Devices
75T20XX
FIGURE 2: Crystal Connections
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| 75T2091-IH | DTMF Transceivers |
| 75V16F64GS16 | 64 Mbit FLASH MEMORY AND 16 Mbit PSEUDO SRAM STACKED MULTI-CHIP PACKAGE (MCP) |
| 7628 | T-1 Subminiature Lamps |
| 7660 | Wallmount ULTRX Series Fiberglass Enclosure; NEMA Type:1, 2, 4, 4X, 12, 13; Enclosure Material:Fiberglass; External Height:30.51"; External Width:24.11"; External Depth:12.64"; Enclosure Color:Light Gray |
| 7632 | T-1 Subminiature Lamps |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| 75T2091-IH | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:DTMF TRANSCEIVERS |
| 75T2091-IP | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:DTMF TRANSCEIVERS |
| 75T43100S50BS | 制造商:Integrated Device Technology Inc 功能描述:IP Co-Processor 304-Pin BGA 制造商:Integrated Device Technology Inc 功能描述:IP CO-PROCESSOR 32K ENTRIES 304SBGA - Trays |
| 75T43100S66BS | 制造商:Integrated Device Technology Inc 功能描述:IP CO-PROCESSOR 32K ENTRIES 304SBGA - Trays |
| 75T-501 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:TRIMMER 500R |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。