[Hackrf-dev] HackRF-dev Digest, Vol 71, Issue 1

[José M. Núñez | CUD Marín]

Hi Ben,

I have some experience in developing a pulse transmitter for radar
applications with HackRF. In the simplest version, I have used the "Vector
Source Block" of GNURadio with this vector:

np.hstack((np.ones(int(tau*samp_rate)), np.zeros(int((pri-tau)*samp_rate))))

where tau is the pulse duration (width), pri is the pulse repetition
interval and samp_rate is the sampling rate.

You can add afterwards, for example, a "Root Raised Cosine Filter" to shape
your pulse...

Regards,
José


-----Mensaje original-----
De: HackRF-dev [mailto:hackrf-dev-bounces at greatscottgadgets.com] En nombre
de hackrf-dev-request at greatscottgadgets.com
Enviado el: sábado, 21 de julio de 2018 7:28
Para: hackrf-dev at greatscottgadgets.com
Asunto: HackRF-dev Digest, Vol 71, Issue 1

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Today's Topics:

   1. Newbie questions related to RADAR emulation project (Ben Greear)


----------------------------------------------------------------------

Message: 1
Date: Fri, 20 Jul 2018 16:50:22 -0700
From: Ben Greear <greearb at candelatech.com>
To: hackrf-dev at greatscottgadgets.com
Subject: [Hackrf-dev] Newbie questions related to RADAR emulation
	project
Message-ID: <5b7a86f0-d68f-0647-a120-a4043ab322b1 at candelatech.com>
Content-Type: text/plain; charset=utf-8; format=flowed

Hello!

First, I'm really enjoying the hackrf so far.  Thanks to all of you who
helped make it possible.

My current application is to make it into a pulse generator.  I have it
basically working, but I am not sure how efficient it is or if it will scale
to larger time intervals...

I am programatically building the vector and passing it to the API like
this.  Also, I know how to program, but I am a newbie at python as well as
hackrf.

self.blocks_vector_source_x_0 = blocks.vector_source_c(vector, True, 1, [])

I build the vector like this:

# globals
vector = [0]

...

     # Build our vector
     for i in range(0, pulse_count):
         vector += [1]*pulse_width
         vector += [0]*pulse_interval

     # Minus 1 because we add a leading zero since I am ignorant of python
an its syntax
     vector += [0]*((sweep_time * 1000) - 1)


My main concern is that the sweep-time I want to support is often large
(like multiple seconds or even minutes).  The vector is going to be really
huge if I pad it with that many zeros.

Is there a better way to have a set of short bursts, and then tell the radio
to stop transmitting for a while before repeating again?

Thanks,
Ben

--
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com



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End of HackRF-dev Digest, Vol 71, Issue 1
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