Features. • Full DTMF receiver. • Less than 35mW power consumption. • Industrial temperature range. • Uses quartz crystal or ceramic. CMPI datasheet, CMPI circuit, CMPI data sheet: CALMIRCO – CMOS Integrated DTMF Receiver,alldatasheet, datasheet, Datasheet search site . comCMOS Integrated DTMF Receiver datasheet search, datasheets, Datasheet search CMPI Datasheet(PDF) 1 Page – California Micro Devices Corp.
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The bandwidths of these filters correspond to the bands enclosing the low-group and high-group tones See Figure 3. OSC3 that can be used to drive clock inputs of other devices. Any subsequent loss of signal condition will cause ESt to fall. Guard Time Adjustment In situations which do not require independent selection of receive and pause, the simple steering circuit of Figure 4 is applicable.
CMPI Hoja de datos ( Datasheet PDF ) – CMOS Integrated DTMF Receiver
Provision is made for connection of a feedback resistor to the op-amp output GS for adjustment of gain. A value for C datashdet 0.
These comparators are provided with a hysteresis to prevent detection of unwanted low-level signals and noise. GT continues to drive high as long as ESt remains high, signaling that a received tone pair has been registered. The steering circuit works in reverse to validate the.
Signal limiting is performed by high- gain comparators.
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Each filter output is followed by a single order switched capacitor section which smooths the signals prior to limiting. The on-chip clock generator requires only a low cost TV. Clock Circuit The internal clock circuit is completed with the addition of a standard television color burst crystal or ceramic resonator having a resonant frequency of 3.
Before the registration of a decoded tone pair, the receiver. The cm88870pi circuit works in reverse to validate the interdigit pause between signals. Increasing t REC improves talk-off performance, since it reduces the probability that tones simulated by speech will maintain signal condition for long enough to be registered.
A typical circuit using this steering configuration is shown in. A logic high on ESt.
V REF which is used to bias the inputs at mid-rail. This check is performed by an external RC time constant driven by E St. The filter section also incorporates notches at Hz and Hz which provides excellent dial tone rejection. A typical circuit using this steering configuration is shown in Figure 1. The contents of the output latch are made available on the 4-bit output bus by raising the three-state control input TOE to a logic high.
This capability together with the. The internal clock circuit is completed with the addition of a. The outputs of the comparators provide full-rail logic swings at the frequencies of the incoming tones. Any subsequent loss of signal. The outputs of the comparators provide full-rail.
The timing requirements for most telecommunica- tion applications are satisfied with this circuit. Guard time adjustment also allows the designer to tailor.
This check is performed by an. When the detector recognizes the simultaneous presence of. Figure 6 shows the DD differential configuration, which permits the adjustment of gain with the feedback resistor R5. In a single-ended configuration, the input pins are connected. Thus, as well as rejecting. C Providing signal condition is maintained ESt remains high for the validation period tV reaches the threshold V of GTP C TSt the steering logic to register the tone pair, thus latching its corresponding 4-bit code See Figure 2 into the output latch.
These comparators are provided with a.
Guard time adjustment also allows the designer to tailor system parameters such as talk-off and noise immunity. Component values are chosen according to the.
The filter section uses a switched capacitor technique for both high and low group filters and dial tone rejection. This may be necessary to meet system specifications which place both accept and reject limits on both tone duration and interdigit pause.
On the other hand, a relatively short t REC with a long t DO would be appropriate for extremely noisy environments where fast acquisition time and immunity to drop-outs would be require- ments.
CMPI datasheet(1/8 Pages) CALMIRCO | CMOS Integrated DTMF Receiver
This capability together with the capability of selecting the steering time constants externally, allows the designer to tailor performance to meet a wide variety of system requirements. The bandwidths of these. Thus, as well as rejecting signals too short to be considered valid, the receiver will tolerate signal interruptions drop outs too short to be considered a valid pause.
This DTMF receiver minimizes external component count by providing an on-chip differential input ampli- fier, clock generator, and a latched three-state interface bus. Providing signal condition is maintained ESt remains high for.
Design information for guard time adjustment is shown in Figure 5. Each filter output is followed by a. A complex averaging algorithm is used to protect against tone simulation by extraneous signals such as voice while providing tolerance to small frequency variations.
California Micro Devices Corp. This DTMF receiver minimizes external component count by providing an on-chip differential input ampli.