Virtual Frequency Meter
The virtual frequency meter is the program for PC and simple measuring instrument, which is
connected to COM to port of the computer. The virtual device allows to measure frequency,
period, time frames and score impulses. The article about it (in russian) was published in
Radiohobby magazine.
You can see
screenshot of the VFM (Virtual Frequency Meter) program below.
Download Circuit Diagram | Download PCB
| Download Layout
Main parameters
| 1.Measuring mode |
Frequency, Period, Time Frames, Score Impulses Metering
|
| 2.Frequency Metering |
| 2.1.Analog Signal Metering |
Frequency range 0.1Hz - 250kHz
Amplitude range 0.1V - 30V |
| 2.2.Digital Signal Metering |
Frequency range 0.1Hz - 5MHz
Low level 0.1V - 2.0V
High level 2.5V - 30V |
| 2.3.Measuring Time |
1mS,10mS,100mS,1S,10S
|
| 3.Period Metering |
| 3.1.Time range |
10mkS - 10S
|
| 3.2.Accuracy |
0.1mkS
|
| 3.3.Measuring Time |
1,10,100,1000 Periods
|
| 3.4.Input Signal |
Analog or Digital
|
| 4.Time Frames Metering |
| 4.1.Time range |
10mkS - 10S
|
| 4.2.Accuracy |
0.1mkS
|
| 4.3.Input Signal |
Analog or Digital
|
The device is mounted in casing of 25pin connector.
See photo. Sorry for photo quality.
The device has supply from signal lines of COM port only. In programing
mode it needs an external +5V.
Components: resistors and capacitors - 1206type, transistors - BCW32L(npn)
BC859C(pnp),diodes - BAS32L, zener diodes - BZX84-C4V7, quartz 10MHz.
See also about power making from PC RS-232
here
Download software and firmware
|
