|
|
PDF AN795 Data sheet ( Hoja de datos )
| Número de pieza | AN795 | |
| Descripción | Voltage to Frequency / Frequency to Voltage Converter | |
| Fabricantes | Microchip | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de AN795 (archivo pdf) en la parte inferior de esta página. Total 15 Páginas | ||
|
No Preview Available !
www.DataSheet4U.com
AN795
Voltage-to-Frequency/Frequency-to-Voltage Converter
Author: Michael O. Paiva,
Microchip Technology, Inc.
RATIOMETRIC MEASUREMENT (ANALOG DIVISION)
One of the most difficult circuits to build is one which will divide one analog signal by another. Two voltage-to-frequency (V/F) converters
can do such division with ease. The numerator is counted directly as a signal, while the denominator forms the time base.
V1 TC9400
V/F
V2 TC9400
V/F
÷N
One
Shot
Output = N
V1
V2
Latch
Counter
One
Shot
Reset
Latch
FIGURE 1: Ratiometric measurement (analog division).
RPM/SPEED INDICATOR
Flow rates and revolutions per second are nothing more than frequency signals, since they measure the number of events per time
period. Optical and magnetic sensors will convert these flows and revolutions into a digital signal which, in turn, can be converted to a
proportional voltage by the use of a frequency-to-voltage (F/V) converter. A simple voltmeter will then give a visual indication of the
speed.
Analog Display
Speed
Sensor
TC9400
F/V
(Optical or Magnetic)
FIGURE 2: RPM/speed indicator.
RPM
DVM Display
RPM
© 2002 Microchip Technology, Inc.
DS00795A-page 1
1 page  
www.DataSheet4U.com
AN795
LONG-TERM INTEGRATOR FOR BIPOLAR (±) SIGNALS
When the input signal is negative as well as positive, there has to be a way of generating "negative" frequencies. An absolute value
circuit accomplishes this by giving the V/F converter a positive voltage only; and also telling the counter to count up for a positive
voltage and to count down for a negative voltage.
1MΩ
47kΩ 500kΩ
TC9400
V/F
47kΩ
VIN
–
Op
Amp
+
–Op
Amp
+
Up/Down
Counter
Up/Down
Reset
Absolute Value Circuit
FIGURE 10: Long-term integrator for bipolar (±) signals.
ANALOG SIGNAL TRANSMISSION OVER TELEPHONE LINES
The TC9400's square-wave output is ideal for transmitting analog data over telephone lines. A square wave is actually preferred over
a pulse waveform for data transmission, since the square wave takes up less frequency spectrum.
The square wave's spectrum can be further reduced by use of low-pass filters.
At the other end of the telephone line, the TC9400 converts the frequency signal back into a voltage output linearly proportional to the
original input voltage.
VIN
9400
V/F
Telephone
Telephone
System Linearity ~ 0.03%
FIGURE 11: Analog signal transmission over telephone lines.
TC9400
F/V
VOUT
© 2002 Microchip Technology, Inc.
DS00795A-page 5
5 Page 
www.DataSheet4U.com
AN795
WIDE FREQUENCY RANGE PULSE GENERATOR
The TC9400 V/F converter is useful in the laboratory as a portable, battery-operated, low-cost frequency source. The TC9400
provides both pulse and square-wave outputs. By adding an op-amp integrator, a triangular waveform can also be generated. The
outputs can be frequency-modulated via the FM input.
V+
Frequency
Adjust
FM
Input
TC9400
V/F
FOUT
1/2 FOUT
–
Op
Amp
+
FIGURE 23: Wide frequency range pulse generator.
FREQUENCY MULTIPLIER/DIVIDER WITH INFINITE RESOLUTION
Frequency scaling can easily be performed by first converting the incoming frequency into a proportional DC voltage. This is
accomplished by using the TC9400 in the F/V mode. Once the frequency is in a voltage format, it is easy to scale this voltage up or
down by use of a single potentiometer. The resultant voltage is then applied to a TC9400 V/F converter, which generates a
proportional output frequency.
Since the potentiometer is infinitely variable, the division/multiplication factor can be any number, including fractions (K1 is simply
VOUT/FIN, while K2 is FOUT/VIN).
VOUT
FIN
TC9400 R1
F/V R2
VIN TC9400
V/F
FOUT
)FOUT = K1 K2
R2
R1 + R2
FIN
FIGURE 24: Frequency multiplier/divider with infinite resolution.
© 2002 Microchip Technology, Inc.
DS00795A-page 11
11 Page | ||
| Páginas | Total 15 Páginas | |
| PDF Descargar | [ Datasheet AN795.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| AN7900F | 3-pin Negative Output Voltage Regulators 1A Type |  Panasonic Semiconductor |
| AN7900F | 3-pin Negative Output Voltage Regulators (1A Type) | Panasonic Semiconductor |
| AN7900T | 3-pin Negative Output Voltage Regulators 1A Type | Panasonic Semiconductor |
| AN7905F | 3-pin Negative Output Voltage Regulators (1A Type) | Panasonic Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |